Dual Cure Sealants

ABSTRACT

Compositions that are curable by free radical redox reactions are disclosed. Free radical curing reactions between polythiols and polyalkyenyls are initiated by the reaction of metal complexes and organic peroxides. The compositions are useful as sealants.

This application claims the benefit under 35 U.S.C. § 119(e) of U.S.Provisional Application No. 62/517,648 filed on Jun. 9, 2017, which isincorporated by reference in its entirety.

FIELD

The disclosure relates to compositions that are curable by free radicalredox reactions are disclosed. Free radical curing reactions betweenpolythiols and polyalkenyls are initiated by the reaction of metalcomplexes and organic peroxides. The compositions are useful assealants.

BACKGROUND

Sealants that are curable using ultraviolet (UV) radiation are useful inin a number of applications. UV-curable coatings and sealants can bestored as a single component and can have an extended application time.Although able to provide highly reliable seals in certain applicationsthe thickness or geometry of a seal can prevent the ultraviolet lightneeded to initiate the free-radical curing reaction from reaching allportions of the applied sealant. Incomplete, insufficient, and/orinhomogeneous exposure to the ultraviolet light can result in a sealantthat is not completely cured or that will only cure after anunacceptably long period of time. Furthermore, in some seals it is notpossible to fully irradiate the uncured sealant.

Dual cure systems that combine a UV-initiated free radical curingreaction and a redox initiated free radical reaction can be combined toprovide a sealant that will at least partially cure following exposureto UV radiation and subsequently continue to cure through aredox-initiated free radical reaction. Such combined dual-cure sealantsare disclosed, for example, in PCT International Application No. WO2016/106352, which discloses free radical reactions initiated by UVradiation and by a peroxide-amine redox reaction.

Alternative dual cure and dark cure sealants that at least partiallycure upon exposure to UV radiation and continue to cure over an extendedperiod of time are desired.

SUMMARY

According to the present invention, compositions comprise a polythiol,wherein the polythiol comprises a thiol-terminated prepolymer; apolyalkenyl, wherein the polyalkenyl comprises an alkenyl-terminatedprepolymer, a polyalkenyl monomer, or a combination thereof, a metalcomplex; and an organic peroxide.

According to the present invention, cured sealants are prepared from acomposition according to the present invention.

According to the present invention, parts are sealed with a curedsealant according to the present invention.

According to the present invention, vehicles comprise a cured sealantaccording to the present invention.

According to the present invention, aerospace vehicles comprise a curedsealant according to the present invention.

According to the present invention, methods of sealing a part compriseapplying the composition according to the present invention to a part;and allowing the applied composition to cure, to seal the part.

According to the present invention, sealant systems comprise a firstpart, wherein the first part comprises a polyalkenyl; and a second part,wherein the second part comprises a polythiol; wherein the first partcomprises a metal complex and the second part comprises an organicperoxide; or wherein the first part comprises an organic peroxide andthe second part comprises a metal complex.

According to the present invention, sealants are prepared from a sealantsystem according to the present invention, wherein the first part andthe second part are combined.

According to the present invention, parts are sealed with a sealantsystem according to the present invention.

According to the present invention, vehicles comprise a cured sealantaccording to the present invention.

According to the present invention, aerospace vehicles comprise a curedsealant according to the present invention.

According to the present invention, methods of sealing a part, comprisecombining the first part and the second part of the sealant systemaccording to the present invention to provide a sealant; applying thesealant to a part; and allowing the applied sealant to cure, to seal thepart.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustration purposes only. Thedrawings are not intended to limit the scope of the present disclosure.

FIG. 1 shows a reaction scheme for a UV-initiated free radical reactionbetween a thiol and a alkenyl.

FIG. 2 shows a reaction scheme for the generation of free radicals usingthe reaction between an organic peroxide and a metal complex.

FIG. 3 is a chart showing the hardness of sealants provided by thepresent disclosure under different curing conditions.

FIG. 4 is a chart showing the depth of cure of sealants provided by thepresent disclosure following UV irradiation.

FIG. 5 is a chart showing physical properties of sealants provided bythe present disclosure under different curing conditions.

FIG. 6 is a chart showing the hardness of sealants provided by thepresent disclosure having different amounts of metal complex and organicperoxide.

FIG. 7 is a chart showing the cure depth of sealants provided by thepresent disclosure having different amounts of metal complex and organicperoxide.

FIG. 8 is a chart showing the extrusion rate of sealants provided by thepresent disclosure after combining the polythiol component and thepolyalkenyl component.

FIG. 9 is a chart showing the hardness and depth of cure of sealantsprovided by the present disclosure having different amounts of metalcomplex and organic peroxide.

FIG. 10 is a chart showing the hardness and cure depth of sealantsprovided by the present disclosure having different amounts of organicanion.

FIG. 11 is a chart showing the hardness of sealants provided by thepresent disclosure under different curing conditions.

FIG. 12 is a chart showing physical properties of sealants provided bythe present disclosure under different curing conditions.

FIG. 13 is a chart showing the application time and tack free time forvarious short cure sealant formulations.

FIG. 14 is a chart showing the Shore A hardness of short cure sealantscured under UV and dark conditions.

FIG. 15 is a chart showing the Shore A hardness of sealants measuredwithin a few minutes following UV exposure.

FIG. 16A is a chart showing the application time for certain of theshort cure, dual cure sealant formulations presented in Table 13.

FIG. 16B is a chart showing the open time for certain of the short cure,dual cure sealant formulations presented in Table 13.

FIG. 17 is a chart showing the Shore A hardness of fully cured sealantscured under UV and dark cure conditions.

FIG. 18 is a chart showing the Shore A hardness of sealants measuredwithin a few minutes following exposure to UV curing conditions.

DETAILED DESCRIPTION

For purposes of the following detailed description, it is to beunderstood that embodiments provided by the present disclosure mayassume various alternative variations and step sequences, except whereexpressly specified to the contrary. Moreover, other than in anyoperating examples, or where otherwise indicated, all numbersexpressing, for example, quantities of ingredients used in thespecification and claims are to be understood as being modified in allinstances by the term “about.” Accordingly, unless indicated to thecontrary, the numerical parameters set forth in the followingspecification and attached claims are approximations that may varydepending upon the desired properties to be obtained by the presentinvention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard variation found in theirrespective testing measurements.

Also, it should be understood that any numerical range recited herein isintended to include all sub-ranges subsumed therein. For example, arange of “1 to 10” is intended to include all sub-ranges between (andincluding) the recited minimum value of 1 and the recited maximum valueof 10, that is, having a minimum value equal to or greater than 1 and amaximum value of equal to or less than 10.

A dash (“-”) that is not between two letters or symbols is used toindicate a point of bonding for a substituent or between two atoms. Forexample, —CONH₂ is attached through the carbon atom.

“Alkanediyl” refers to a diradical of a saturated or unsaturated,branched or straight-chain, acyclic hydrocarbon group, having, forexample, from 1 to 18 carbon atoms (C₁₋₁₈), from 1 to 14 carbon atoms(C₁₋₁₄), from 1 to 6 carbon atoms (C₁₋₆), from 1 to 4 carbon atoms(C₁₋₄), or from 1 to 3 hydrocarbon atoms (C₁₋₃). It will be appreciatedthat a branched alkanediyl has a minimum of three carbon atoms. Analkanediyl can be C₂₋₁₄ alkanediyl, C₂₋₁₀ alkanediyl, C₂₋₈ alkanediyl,C₂₋₆ alkanediyl, C₂₋₄ alkanediyl, or C₂₋₃ alkanediyl. Examples ofalkanediyl groups include methane-diyl (—CH₂—), ethane-1,2-diyl(—CH₂CH₂—), propane-1,3-diyl and iso-propane-1,2-diyl (e.g., —CH₂CH₂CH₂—and —CH(CH₃)CH₂—), butane-1,4-diyl (—CH₂CH₂CH₂CH₂—), pentane-1,5-diyl(—CH₂CH₂CH₂CH₂CH₂—), hexane-1,6-diyl (—CH₂CH₂CH₂CH₂CH₂CH₂—),heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl,and dodecane-1,12-diyl. Alkanediyl groups can include single, double,and/or triple bonds between carbon atoms.

“Alkanecycloalkane” refers to a saturated hydrocarbon group having oneor more cycloalkyl and/or cycloalkanediyl groups and one or more alkyland/or alkanediyl groups, where cycloalkyl, cycloalkanediyl, alkyl, andalkanediyl are defined herein. Each cycloalkyl and/or cycloalkanediylgroup(s) can be C₃₋₆, C₅₋₆, cyclohexyl or cyclohexanediyl. Each alkyland/or alkanediyl group(s) can be C₁₋₆, C₁₋₄, C₁₋₃, methyl, methanediyl,ethyl, or ethane-1,2-diyl. An alkanecycloalkane group can be C₄₋₁₈alkanecycloalkane, C₄₋₁₆ alkanecycloalkane, C₄₋₁₂ alkanecycloalkane,C₄₋₈ alkanecycloalkane, C₆₋₁₂ alkanecycloalkane, C₆₋₁₀alkanecycloalkane, or C₆₋₉ alkanecycloalkane. Examples ofalkanecycloalkane groups include 1,1,3,3-tetramethylcyclohexane andcyclohexylmethane.

“Alkanecycloalkanediyl” refers to a diradical of an alkanecycloalkanegroup. An alkanecycloalkanediyl group can be C₄₋₁₈alkanecycloalkanediyl, C₄₋₁₆ alkanecycloalkanediyl, C₄₋₁₂alkanecycloalkanediyl, C₄₋₈ alkanecycloalkanediyl, C₆₋₁₂alkanecycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl, or C₆₋₉alkanecycloalkanediyl. Examples of alkanecycloalkanediyl groups include1,1,3,3-tetramethylcyclohexane-1,5-diyl and cyclohexylmethane-4,4′-diyl.

“Alkanearene” refers to a hydrocarbon group having one or more aryland/or arenediyl groups and one or more alkyl and/or alkanediyl groups,where aryl, arenediyl, alkyl, and alkanediyl are defined here. Each aryland/or arenediyl group(s) can be C₆₋₁₂, C₆₋₁₀, phenyl or benzenediyl.Each alkyl and/or alkanediyl group(s) can be C₁₋₆, C₁₋₄, C₁₋₃, methyl,methanediyl, ethyl, or ethane-1,2-diyl. An alkanearene group can beC₄₋₁₈ alkanearene, C₄₋₁₆ alkanearene, C₄₋₁₂ alkanearene, C₄₋₈alkanearene, C₆₋₁₂ alkanearene, C₆₋₁₀ alkanearene, or C₆₋₉ alkanearene.Examples of alkanearene groups include diphenyl methane.

“Alkanearenediyl” refers to a diradical of an alkanearene group. Analkanearenediyl group is C₄₋₁₈ alkanearenediyl, C₄₋₁₆ alkanearenediyl,C₄₋₁₂ alkanearenediyl, C₄₋₈ alkanearenediyl, C₆₋₁₂ alkanearenediyl,C₆₋₁₀ alkanearenediyl, or C₆₋₉ alkanearenediyl. Examples ofalkanearenediyl groups include diphenyl methane-4,4′-diyl.

“Alkenyl” group refers to the structure —CR═C(R)₂ where the alkenylgroup is a terminal group and is bonded to a larger molecule. In suchembodiments, each R may independently comprise, for example, hydrogenand C₁₋₃ alkyl. Each R can be hydrogen and an alkenyl group can have thestructure —CH═CH₂.

“Alkoxy” refers to a —OR group where R is alkyl as defined herein.Examples of alkoxy groups include methoxy, ethoxy, n-propoxy,isopropoxy, and n-butoxy. An alkoxy group can be C₁₋₈ alkoxy, C₁₋₆alkoxy, C₁₋₄ alkoxy, or C₁₋₃ alkoxy.

“Alkyl” refers to a monoradical of a saturated or unsaturated, branchedor straight-chain, acyclic hydrocarbon group having, for example, from 1to 20 carbon atoms, from 1 to 10 carbon atoms, from 1 to 6 carbon atoms,from 1 to 4 carbon atoms, or from 1 to 3 carbon atoms. It will beappreciated that a branched alkyl has a minimum of three carbon atoms.An alkyl group can be C₁₋₆ alkyl, C₁₋₄ alkyl, or C₁₋₃ alkyl. Examples ofalkyl groups include methyl, ethyl, n-propyl, iso-propyl, n-butyl,iso-butyl, tert-butyl, n-hexyl, n-decyl, and tetradecyl. An alkyl groupis C₁₋₆ alkyl, C₁₋₄ alkyl, and C₁₋₃ alkyl.

“Arenediyl” refers to diradical monocyclic or polycyclic aromatic group.Examples of arenediyl groups include benzene-diyl and naphthalene-diyl.An arenediyl group can be C₆₋₁₂ arenediyl, C₆₋₁₀ arenediyl, C₆₋₉arenediyl, or benzene-diyl.

“Cycloalkanediyl” refers to a diradical saturated monocyclic orpolycyclic hydrocarbon group. A cycloalkanediyl group can be C₃₋₁₂cycloalkanediyl, C₃₋₈ cycloalkanediyl, C₃₋₆ cycloalkanediyl, or C₅₋₆cycloalkanediyl. Examples of cycloalkanediyl groups includecyclohexane-1,4-diyl, cyclohexane-1,3-diyl and cyclohexane-1,2-diyl.

“Cycloalkyl” refers to a saturated monocyclic or polycyclic hydrocarbonmono-radical group. A cycloalkyl group can be C₃₋₁₂ cycloalkyl, C₃₋₈cycloalkyl, C₃₋₆ cycloalkyl, or C₅₋₆ cycloalkyl.

“Heteroalkanediyl” refers to an alkanediyl group in which one or more ofthe carbon atoms are replaced with a heteroatom, such as N, O, S, or P.In a heteroalkanediyl, the one or more heteroatoms can comprise N or O.

“Heterocycloalkanediyl” refers to a cycloalkanediyl group in which oneor more of the carbon atoms are replaced with a heteroatom, such as N,O, S, or P. In a heterocycloalkanediyl, the one or more heteroatoms cancomprise N or O.

“Heteroarenediyl” refers to an arenediyl group in which one or more ofthe carbon atoms are replaced with a heteroatom, such as N, O, S, or P.In a heteroarenediyl, the one or more heteroatoms can comprise N or O.

A “polyalkenyl” refers to a compound having at least two alkenyl groups.The at least two alkenyl groups can be terminal alkenyl groups and suchpolyalkenyls can be referred to as alkenyl-terminated compounds. Alkenylgroups can also be pendent alkenyl groups. A polyalkenyl can be adialkenyl, having two alkenyl groups. A polyalkenyl can have more thantwo alkenyl groups such as from three to six alkenyl groups. Apolyalkenyl can comprise a single type of polyalkenyl, can be acombination of polyalkenyls having the same alkenyl functionality, orcan be a combination of polyalkenyls having different alkenylfunctionalities.

A “polyalkenyl prepolymer” refers to a polyalkenyl having at least onerepeat unit in the polyalkenyl backbone. A polyalkenyl prepolymergenerally has a molecular weight in the range from 500 Daltons to 6,000Daltons, such as from 500 Daltons to 4,000 Daltons or from 500 Daltonsto 2,000 Daltons.

A “monomeric polyalkenyl” refers to a polyalkenyl that does not includerepeat units in the polyalkenyl backbone. A monomeric polyalkenylgenerally has a molecular weight that is less than that of a polyalkenylprepolymer. Monomeric polyalkenyls can be difunctional or have analkenyl functionality greater than two.

“Formed from” or “prepared from” denotes open, e.g., comprising, claimlanguage. As such, it is intended that a composition “formed from” or“prepared from” a list of recited components be a composition comprisingat least the recited components or the reaction product of at least therecited components, and can further comprise other, non-recitedcomponents used to form or prepare the composition.

“Reaction product of” means a chemical reaction product(s) of at leastthe recited reactants, and can include partial reaction products as wellas fully reacted products and other reaction products that are presentin a lesser amount. For example, a “prepolymer comprising the reactionproduct of reactants” refers to a prepolymer or combination ofprepolymers that are the reaction product of at least the recitedreactants. The reactants can further comprise additional reactants.

A compound having a thiol functionality or an alkenyl functionalityrefers to a compound which has reactive thiol or alkenyl groups,respectively. The reactive thiol or alkenyl groups may be terminalgroups bonded to the ends of the molecule, may be bonded to the backboneof the molecule, or the compound may contain thiol or alkenyl groupsthat are terminal groups or are bonded to the backbone.

As used herein, the term “cure” or “cured” as used in connection with acomposition, e.g., “composition when cured” or a “cured composition”,means that any curable or crosslinkable components of the compositionare at least partially reacted or crosslinked.

The term “equivalent” refers to the number of functional reactive groupsof the substance. “Equivalent weight” is effectively equal to themolecular weight of a substance, divided by the valence or number offunctional reactive groups of the substance.

A “backbone” of a prepolymer refers to the segment between the reactiveterminal groups. A prepolymer backbone typically includes repeatingsubunits. For example, the backbone of a polythiol HS—[R]_(n)—SH is—[R]_(n)—.

A “core” of a polyfunctionalizing agent B(-V)_(z) refers to the moietyB.

A “core” of a compound or a polymer refers to the segment between thereactive terminal groups. For example, the core of a polythiol HS—R—SHwill be —R—. A core of a compound or prepolymer can also be referred toas a backbone of a compound or a backbone of a prepolymer. A core of apolyfunctionalizing agent can be an atom or a structure such as acycloalkane, a substituted cycloalkane, heterocycloalkane, substitutedheterocycloalkane, arene, substituted arene, heteroarene, or substitutedheteroarene from which moieties having a reactive functional are bonded.

“Core of a diisocyanate” refers to the moiety forming the diisocyanatewithout the isocyanate groups. For example, the core of a diisocyanatehaving the structure O═C═N—R⁴—N═C═O is represented by —R⁴—. For example,a core of the aliphatic diisocyanate 4,4′-methylene dicyclohexyldiisocyanate has the structure:

“Prepolymer” refers to oligomers, homopolymers, and copolymers. Forthiol-terminated prepolymers, molecular weights are number averagemolecular weights “Mn” as determined by end group analysis using iodinetitration. For prepolymers that are not thiol-terminated, the numberaverage molecular weights are determined by gel permeationchromatography using polystyrene standards. A prepolymer comprisesreactive groups capable of reacting with another compound such as acuring agent or crosslinker to form a cured polymer. A prepolymer suchas a chain-extended polythioether prepolymer provided by the presentdisclosure can be combined with a curing agent to provide a curablecomposition, which can cure to provide a cured polymer network.Prepolymers are liquid at room temperature (21° C. to 25° C.) andpressure (760 torr; 101 kPa).

A prepolymer includes multiple repeating subunits bonded to each otherthan can be the same or different. The multiple repeating subunits makeup the backbone of the prepolymer.

A “curable composition” refers to a composition that comprises at leasttwo reactants capable of reacting to form a cured composition. Forexample, a curable composition can comprise a isocyanate-terminatedchain-extended polythioether prepolymer and a polyamine capable ofreacting to form a cured polymer. A curable composition may include acatalyst for the curing reaction and other components such as, forexample, fillers, pigments, and adhesion promoters. A curablecomposition may be curable at room temperature, or may require exposureto elevated temperature such as a temperature above room temperature orother condition(s) to initiate and/or to accelerate the curing reaction.A curable composition may initially be provided as a two-partcomposition including, for example, a separate base component and anaccelerator component. The base composition can contain one of thereactants participating in the curing reaction such as anisocyanate-terminated chain-extended polythioether prepolymer and theaccelerator component can contain the other reactant such as apolyamine. The two components can be mixed shortly before use to providea curable composition. A curable composition can exhibit a viscositysuitable for a particular method of application. For example, a Class Asealant composition, which is suitable for brush-on applications, can becharacterized by a viscosity from 1 poise to 500 poise (0.1 Pa-sec to 50Pa-sec). A Class B sealant composition, which is suitable for filletseal applications, can be characterized by a viscosity from 4,500 poiseto 20,000 poise (450 Pa-sec to 2,000 Pa-sec). A Class C sealantcomposition, which is suitable for fay seal applications, can becharacterized by a viscosity from 500 poise to 4,500 poise (50 Pa-sec to450 Pa-sec). The viscosity of the compositions is measured as describedherein. After the two components of a sealant system are combined andmixed, the curing reaction can proceed and the viscosity of the curablecomposition can increase and at some point, will no longer be workable,as described herein. The duration between when the two components aremixed to form the curable composition and when the curable compositioncan no longer be reasonably or practically applied to a surface for itsintended purpose can be referred to as the working time. As can beappreciated, the working time can depend on a number of factorsincluding, for example, the curing chemistry, the catalyst used, theapplication method, and the temperature. Once a curable composition isapplied to a surface (and during application), the curing reaction canproceed to provide a cured composition. A cured composition develops atack-free surface, cures, and then fully cures over a period of time. Acurable composition can be considered to be cured when the hardness ofthe surface is at least 30 Shore A for a Class B sealant or a Class Csealant. After a sealant has cured to a hardness of 30 Shore A it cantake from several days to several weeks for a curable composition fullycure. A composition is considered fully cured when the hardness nolonger increases. Depending on the formulation, a fully cured sealantcan exhibit, for example, a hardness from 40 Shore A to 70 Shore A,determined according to ISO 868. For coating applications, a curablecomposition can have a viscosity, for example, from 200 cps to 800 cps0.2 Pa-sec to 0.8 Pa-sec). For sprayable coating and sealantcompositions, a curable composition can have a viscosity, for example,from 15 cps to 100 cps (0.015 Pa-sec to 0.1 Pa-sec), such as from 20 cpsto 80 cps (0.02 Pa-sec to 0.0.8 Pa-sec).

“Substituted” refers to a group in which one or more hydrogen atoms areeach independently replaced with the same or different substituent(s). Asubstituent can comprises halogen, —S(O)₂OH, —S(O)₂, —SH, —SR where R isC₁₋₆ alkyl, —COOH, —NO₂, —NR₂ where each R independently compriseshydrogen and C₁₋₃ alkyl, —CN, ═O, C₁₋₆ alkyl, —CF₃, —OH, phenyl, C₂₋₆heteroalkyl, C₅₋₆ heteroaryl, C₁₋₆ alkoxy, or —COR where R is C₁₋₆alkyl. A substituent can be —OH, —NH₂, or C₁₋₃ alkyl.

“Derived from” as in “a moiety derived from a compound” refers to amoiety that is generated upon reaction of a parent compound with areactant. For example, a bis(alkenyl) compound CH₂═CH—R—CH═CH₂ can reactwith another compound such as two compounds having thiol groups toproduce the moiety —(CH₂)₂—R—(CH₂)₂— derived from the reaction of thealkenyl groups with the thiol groups. For example, for a parentdiisocyanate having the structure O═C═N—R—N═C═O, a moiety derived fromthe diisocyanate has the structure —C(O)—NH—R—NH—C(O)—. As anotherexample, for a parent non-linear short chain diol having the structureHO—R—OH, a moiety derived from the non-linear short-chain diol has thestructure —O—R—O—.

“Derived from the reaction of -V with a thiol” refers to a moiety -V′-that results from the reaction of a thiol group with a moiety comprisinga terminal group reactive with a thiol group. For example, a group V-can comprise CH₂═CH—CH₂—O—, where the terminal alkenyl group CH₂═CH— isreactive with a thiol group —SH. Upon reaction with a thiol group, themoiety -V′- is —CH₂—CH₂—CH₂—O—.

“Dark cure” refers to curing mechanisms that do not require exposure toactinic radiation such as UV radiation to initiate the reaction. Actinicradiation may be applied to a dark cure system to accelerate curing ofall or a part of a composition, but exposing the composition to actinicradiation is not necessary to cure the sample. A dark cure compositioncan fully cure under dark conditions without exposure to actinicradiation.

Glass transition temperature T_(g) is determined by dynamic mechanicalanalysis (DMA) using a TA Instruments Q800 apparatus with a frequency of1 Hz, an amplitude of 20 microns, and a temperature ramp of −80° C. to25° C., with the T_(g) identified as the peak of the tan δ curve.

When reference is made to a chemical group defined, for example, by anumber of carbon atoms, the chemical group is intended to include allsub-ranges of carbon atoms as well as a specific number of carbon atoms.For example, a C₂₋₁₀ alkanediyl includes a C₂₋₄ alkanediyl, C₅₋₇alkanediyl, and other sub-ranges, a C₂ alkanediyl, a C₆ alkanediyl, andalkanediyls having other specific number(s) of carbon atoms from 2 to10.

A polyfunctionalizing agent can have the structure of Formula (1):

B¹(-V)_(z)  (1)

where B¹ is the core of the polyfunctionalizing agent, each V is amoiety terminated in a reactive functional group such as a thiol group,an alkenyl group, an epoxy group, an isocyanate group, or a Michaelacceptor group, and z is an integer from 3 to 6, such as 3, 4, 5, or 6.In polyfunctionalizing agents of Formula (1), each -V can have thestructure, for example, —R—SH or —R—CH═CH₂, where R can be, for example,C₂₋₁₀ alkanediyl, C₂₋₁₀ heteroalkanediyl, substituted C₂₋₁₀ alkanediyl,or substituted C₂₋₁₀ heteroalkanediyl.

When the moiety V is reacted with another compound the moiety -V¹-results and is said to be derived from the reaction with the othercompound. For example, when V is —R—CH═CH₂ and is reacted, for example,with a thiol group, the moiety V¹ is —R—CH₂—CH₂— is derived from thereaction.

In polyfunctionalizing agents of Formula (1), B¹ can be, for exampleC₂₋₈ alkane-triyl, C₂₋₈ heteroalkane-triyl, C₅₋₈ cycloalkane-triyl, C₅₋₈heterocycloalkane-triyl, substituted C₅₋₈ cycloalkene-triyl, C₅₋₈heterocycloalkane-triyl, C₆ arene-triyl, C₄₋₅ heteroarene-triyl,substituted C₆ arene-triyl, or substituted C₄₋₅ heteroarene-triyl.

In polyfunctionalizing agents of Formula (1), B¹ can be, for example,C₂₋₈ alkane-tetrayl, C₂₋₈ heteroalkane-tetrayl, C₅₋₁₀cycloalkane-tetrayl, C₅₋₁₀ heterocycloalkane-tetrayl, C₆₋₁₀arene-tetrayl, C₄ heteroarene-tetrayl, substituted C₂₋₈ alkane-tetrayl,substituted C₂₋₈ heteroalkane-tetrayl, substituted C₅₋₁₀cycloalkane-tetrayl, substituted C₅₋₁₀ heterocycloalkane-tetrayl,substituted C₆₋₁₀ arene-tetrayl, and substituted C₄₋₁₀heteroarene-tetrayl.

Examples of suitable alkenyl-terminated polyfunctionalizing agentsinclude triallyl cyanurate (TAC), triallylisocyanurate (TAIC),1,3,5-triallyl-1,3,5-triazinane-2,4,6-trione,1,3-bis(2-methylallyl)-6-methylene-5-(2-oxopropyl)-1,3,5-triazinone-2,4-dione,tris(allyloxy)methane, pentaerythritol triallyl ether,1-(allyloxy)-2,2-bis((allyloxy)methyl)butane,2-prop-2-ethoxy-1,3,5-tris(prop-2-enyl)benzene,1,3,5-tris(prop-2-enyl)-1,3,5-triazinane-2,4-dione, and1,3,5-tris(2-methylallyl)-1,3,5-triazinane-2,4,6-trione,1,2,4-trivinylcyclohexane, and combinations of any of the foregoing.

A polyfunctionalizing agent of Formula (1) can be thiol terminated.

Examples of suitable trifunctional thiol-terminated polyfunctionalizingagents include, for example, 1,2,3-propanetrithiol,1,2,3-benzenetrithiol, 1,1,1-butanetrithiol, heptane-1,3-7-trithiol,1,3,5-triazine-2,4-6-trithiol, isocyanurate-containing trithiols, andcombinations thereof, as disclosed in U.S. Application Publication No.2010/0010133, and the polythiols described in U.S. Pat. Nos. 4,366,307;4,609,762; and 5,225,472. Combinations of polyfunctionalizing agents mayalso be used.

Examples of suitable polythiol polyfunctionalizing agents includepentaerythritol tetra(3-mercapto-propionate) (PETMP),trimethylol-propane tri(3-mercaptopropionate) (TMPMP), glycoldi(3-mercaptopropionate) (GDMP),tris[2-(3-mercapto-propionyloxy)ethyl]isocyanurate (TEMPIC),di-pentaerythritol hexa(3-mercaptopropionate) (di-PETMP),tri(3-mercaptopropionate) pentaerythritol, triethylolethanetri-(3-mercaptopropionate), and combinations of any of the foregoing.

Examples of suitable mercapto-acetate polythiol polyfunctionalizingagents include pentaerythritol tetramercaptoacetate (PRTMA),trimethylolpropane trimercaptoacetate (TMPMA), glycol dimercaptoacetate(GDMA), ethyleneglycol dimercaptoacetate, di-trimethylolpropanetetramercaptoacetate, and combinations of any of the foregoing.

Examples of suitable polythiol polyfunctionalizing agents includepentaerythritol tetra-acrylate,tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate,2,3-di(2-mercaptoethylthio)-1-propane-thiol, dimercaptodiethylsulfide(2,2′-thiodiethanethiol), dimercaptodioxaoctane(2,2′-(ethylenedioxy)diethanethiol, 1,8-dimercapto-3,6-dioxaoctane, andcombinations of any of the foregoing.

Other examples of polythiol polyfunctionalizing agents and polythiolmonomers include pentaerythritol tetra(3-mercaptopropionate) (PETMP),pentaerythritol tetramercaptoacetate (PETMA), dipentaerythritoltetra(3-mercaptopropionate), dipentaerythritol tetramercaptoacetate,dipentaerythritol penta(3-mercaptopropionate), dipentaerythritolpentamercaptoacetate, dipentaerythritol hexa(3-mercaptopropionate),dipentaerythritol hexamercaptoacetate, ditrimethylolpropanetetra(3-mercaptopropionate), ditrimethylolpropane tetramercaptoacetate,and also alkoxylated, for example, ethoxylated and/or propoxylated, suchas ethoxylated, products of these compounds. Examples include,pentaerythritol tetra(3-mercaptopropionate) (PETMP), pentaerythritoltetramercaptoacetate (PETMA), dipentaerythritoltetra(3-mercaptopropionate), dipentaerythritol tetramercaptoacetate,dipentaerythritol penta(3-mercaptopropionate), dipentaerythritolpentamercaptoacetate, dipentaerythritol hexa(3-mercaptopropionate),dipentaerythritol hexamercaptoacetate, ditrimethylolpropanetetra(3-mercaptopropionate), ditrimethylolpropane tetramercaptoacetate,particularly pentaerythritol tetra(3-mercaptopropionate) (PETMP),pentaerythritol tetramercaptoacetate (PETMA), dipentaerythritolhexa(3-mercaptopropionate), dipentaerythritol hexamercaptoacetate,ditrimethylolpropane tetra(3-mercaptopropionate), andditrimethylolpropane tetramercaptoacetate.

Suitable polythiol polyfunctionalizing agents are commerciallyavailable, for example, from Bruno Bock Thiochemicals under theThiocure® tradename.

“Derived from a polyfunctionalizing agent” refers to a moiety thatresults from the reaction of a polyfunctionalizing agent with a reactivefunctional group. For example, a moiety derived from thepolyfunctionalizing agent triallyl cyanurate:

results in a moiety having the structure:

where the segments are bonded to the other reactants.

“Polyol polyfunctionalizing agent” refers to a polyol having, forexample, from 3 to 6 terminal hydroxyl groups. A polyolpolyfunctionalizing agent can have a molecular weight, for example, lessthan 1,400 Daltons, less than 1,200 Daltons, less than 1,000 Daltons,less than 800 Daltons, less than 700 Daltons, less than 600 Daltons,less than 500 Daltons, less than 400 Daltons, less than 300 Daltons,less than 200 Daltons, or less than 100 Daltons. Polyolpolyfunctionalizing agents can be represented by the formula B⁴(-V)_(z),where B⁴ represents a core of a z-valent polyfunctionalizing agentB⁴(-V)_(z), z is an integer from 3 to 6; and each -V is a moietycomprising a terminal hydroxyl (—OH) group.

“Polythiol polyfunctionalizing agent” refers to a polythiol having, forexample, from 3 to 6 terminal thiol groups. A polythiolpolyfunctionalizing agent can have a molecular weight, for example, lessthan 1,400 Daltons, less than 1,200 Daltons, less than 1,000 Daltons,less than 800 Daltons, less than 700 Daltons, less than 600 Daltons,less than 500 Daltons, less than 400 Daltons, less than 300 Daltons,less than 200 Daltons, or less than 100 Daltons. Polythiolpolyfunctionalizing agents can be represented by the formula B⁴(-V)_(z),where B⁴ represents a core of a z-valent polyfunctionalizing agentB⁴(-V)_(z), z is an integer from 3 to 6; and each -V is a moietycomprising a terminal thiol (—SH) group.

A polythiol or a polyalkenyl can be be a polythiol polyfunctionalizingagent or a polyalkenyl polyfunctionalizing agent, respectively.

“Composition” is intended to encompass a product comprising thespecified components in the specified amounts, as well as any productwhich results, directly or indirectly, from the combination of thespecified ingredients in the specified amounts.

“Molecular weight” refers to a theoretical molecular weight estimatedfrom the chemical structure of a compound such as a monomeric compound,or a number average molecular weight as appropriate for a prepolymerdetermined, for example, using gel permeation chromatography usingpolystyrene standards.

“Application time” refers to the duration during which a curablecomposition can be applied to a surface. The application time can be forexample, at least 2 hours, at least 4 hours, at least 6 hours, at least12 hours, at least 16 hours, at least 20 hours, or at least 24 hours.The application time can depend on the method of application such as,for example, by extrusion, rolling, brushing, or spreading. Theapplication time of a curable composition can be determined by measuringthe extrusion rate of a composition as described in the Examples. Forexample, the application time of a curable composition provided by thepresent disclosure can be defined as the duration until the curablecomposition exhibits an extrusion rate, as determined by extrusionthrough a No. 440 nozzle (Semco, 0.125-inch internal diameter and 4-inchlength, available from PPG Aerospace) at a pressure of 90 psi (620 KPa)is greater than 15 g/min, greater than 30 g/min, or greater than 50g/min. An appropriate application time can depend, for example, on thespecific application method, temperature, humidity, thickness, surfacearea. and volume.

“Tack free time” refers to the duration from the time when co-reactivecomponents are first combined and mixed to form a curable sealant untila coating prepared from the curable sealant exhibits is tack free asdetermined by applying a polyethylene sheet to the surface of thesealant with hand pressure and observing whether sealant adheres to thesurface of the polyethylene sheet.

“Full cure” refers to the duration from the time when co-reactivecomponents are first combined and mixed to form a curable sealant untila coating prepared from the curable sealant exhibits a hardness of atleast Shore 40A at 25° C. and 50% RH. A time to full cure can be, forexample, from 1 week to 2 weeks, from 1 week to 6 weeks, from 2 weeks to5 weeks, or from 3 weeks to 5 weeks.

“Cure time” refers to the duration from the time when the co-reactivecomponents are first combined and mixed to form a curable sealant untila coating prepared from the curable sealant exhibits a hardness of Shore30A at conditions of 25° C. and 50% RH.

Specific gravity is determined according to ASTM D 1475.

Shore A hardness is measured using a Type A durometer in accordance withASTM D2240.

Tensile strength and elongation are measured according to AMS 3279.

Reference is now made to certain compounds, compositions, and methods ofthe present invention. The disclosed compounds, compositions, andmethods are not intended to be limiting of the claims. To the contrary,the claims are intended to cover all alternatives, modifications, andequivalents.

Combinations of metal complexes and organic peroxides can be used asfree radical catalysts for curing compositions such as sealants.Combinations of metal complexes and organic peroxides can also impartuseful dual cure properties to radiation curable sealants such as UVcurable sealants. The cure dynamics can depend on the combination ofmetal complexes and organic peroxides. Using different solvent mixturesto disperse the metal complexes it is also possible to control the geltime of the sealant and control the time to fully cure the sealant underdark conditions. Physical properties and adhesion of sealants curedusing a dark cure redox radial initiated reaction are comparable tothose of sealants cured using actinic radiation only (in the absence ofthe dark cure catalyst system) such as UV-radiation. Such dual curesealants have several advantages. For example, the surface of a sealantcan be rapidly cured by exposure to the radiation enabling the part tobe manipulated and handled while the unexposed portion of the sealantfully cures. Using a dual cure mechanism the surface of a sealant can berapidly cured without exposing the full depth of the sealant to theradiation and thereafter the unexposed sealant can fully cure. Also, ingeometries and configurations where it is not possible to directlyexpose a curable sealant to radiation, a portion of the sealant can beexposed to the radiation thereby initiating dark cure redox curingmechanisms that can propagate through unexposed areas of the sealant.Dual cure mechanisms can further provide opportunities to control thecure rate of a sealant, which can lead to improved properties such asimproved tensile strength, % elongation, solvent resistance, andadhesion.

As illustrated in FIG. 1, unmodified UV-curable compositions based onthiol-ene chemistry react by generation of free radicals when exposed toactinic radiation such as UV radiation in the presence of aphotoinitiator (I). An unmodified UV-curable composition refers to aUV-curable composition that does not include a metal complex/organicperoxide free radical initiator. The free radical generated by thephotoinitiator abstracts a hydrogen from a thiol group creating athienyl radical that can add to an alkylene group, creating asulfur-carbon bond and a 3-carbon radical, which initiates chainpropagation.

In dark cure mode, i.e., when actinic radiation such as UV radiation isnot used to generate free radicals, the disclosure provides an alternateradical initiation mechanism that takes place in absence of actinicradiation. In the disclosed dark cure mechanism, the thiol-enepolymerization proceeds through a controlled generation of free radicalsusing a combination of an organic peroxide and a metal complex in theabsence of actinic radiation. FIG. 2 illustrates the decomposition of anorganic peroxide, tert-butyl peroxybenzoate, in the presence of a metalcomplex to generate free radicals.

After the free radicals are generated as shown in FIG. 2, thepolymerization of the polythiol and polyalkenyl components can continuein the manner as shown in FIG. 1. The use of organic peroxides and metalcomplexes as dark cure free radical catalysts can provide curedcompositions with properties similar to those of UV-cured compositions(without a dark cure catalyst).

Compositions provided by the present disclosure comprise a polythiol, apolyalkenyl, a metal complex, and an organic peroxide. Compositionsprovided by the present disclosure comprise a thiol-terminatedsulfur-containing prepolymer, a polyalkenyl, a metal complex, and anorganic peroxide.

Compositions and sealant formulations provided by the present disclosurecan comprise a thiol-terminated sulfur-containing prepolymer such as athiol-terminated polythioether prepolymer, a thiol-terminatedpolysulfide prepolymer, a thiol-terminated sulfur-containing polyformalprepolymer, a thiol-terminated monosulfide prepolymer, or a combinationof any of the foregoing. A sulfur-containing prepolymer refers to aprepolymer that has one or more thioether —S— and/or sulfide —S—S—groups in the backbone of the prepolymer. Prepolymers that contain onlythiol or other sulfur-containing groups, either as terminal groups or aspendent groups of the prepolymer backbone are not encompassed bysulfur-containing prepolymers. Thus, a prepolymer having the structureHS—R—R(—CH₂—SH)—R—(CH₂)₂—S(O)₂—(CH₂)₂—S(O)₂—CH═CH₂ where each R is amoiety that does not contain a sulfur atom, is not encompassed by asulfur-containing prepolymer; however, the prepolymer comprises twoterminal thiol groups A prepolymer having the structureHS—R—R(—CH₂—SH)—R—(CH₂)₂—S(O)₂—(CH₂)₂—S(O)₂—CH═CH₂ where at least one Ris a moiety that contains a sulfur atom, such as a thioether or sulfidegroup, is encompassed by a sulfur-containing prepolymer. The prepolymerdescribed in the preceding paragraph comprises a terminal thiol groupand at least one sulfur atom in the prepolymer backbone. Insulfur-containing prepolymers provided by the present disclosure thesulfur content of the prepolymer backbone (and not including terminalthiol groups) can be, for example, from 0.1 wt % to 20 wt %, from 0.1 wt% to 10 wt %, form 0.1 wt % to 5 wt %, or from 0.1 wt % to 2 wt %, wherewt % refers to the total weight of the sulfur-containing prepolymer.

A thiol-terminated sulfur-containing prepolymer can comprise athiol-terminated polythioether or a thiol-terminated sulfur-containingprepolymer can comprise a thiol-terminated polysulfide prepolymer. Athiol-terminated sulfur-containing prepolymer may comprise a combinationof different thiol-terminated polythioether prepolymers and/orthiol-terminated polysulfide prepolymers, and the thiol-terminatedpolythioether prepolymers and/or thiol-terminated polysulfideprepolymers may have the same or different functionality. Athiol-terminated sulfur-containing prepolymer can have an average thiolfunctionality from 2 to 6, from 2 to 4, from 2 to 3, from 2.3 to 2.8, orfrom 2.05 to 2.5. For example, a thiol-terminated sulfur-containingprepolymer can comprise a difunctional thiol-terminatedsulfur-containing prepolymer, a trifunctional thiol-terminatedsulfur-containing prepolymer, or a combination thereof. Asulfur-containing prepolymer can comprise a thiol-terminatedsulfur-containing polyformal prepolymer. A sulfur-containing prepolymercan comprise a thiol-terminated monosulfide prepolymer.

Compositions and sealants provided by the present disclosure cancomprise, for example, from 30 wt % to 70 wt %, from 40 wt % to 60 wt %,from 43 wt % to 57 wt %, from 46 wt % to 54 wt %, or from 48 wt % to 52wt % of a thiol-terminated sulfur-containing prepolymer or combinationof thiol-terminated sulfur-containing prepolymers, such as athiol-terminated polythioether prepolymer, a thiol-terminatedpolysulfide prepolymer, a thiol-terminated sulfur-containing polyformalprepolymer, a thiol-terminated monosulfide prepolymer, or a combinationof any of the foregoing, where wt % is based on the total weight of thecurable composition.

A sulfur-containing prepolymer can comprise a thiol-terminatedpolythioether prepolymer. Examples of suitable thiol-terminatedpolythioether prepolymers are disclosed, for example, in U.S. Pat. No.6,172,179, which is incorporated by reference in its entirety. Athiol-terminated polythioether prepolymer can comprise Permapol® P3.1E,Permapol® P3.1E-2.8, Permapol® L56086, or a combination of any of theforegoing, each of which is available from PRC-DeSoto International Inc.Permapol® P3.1E, Permapol® P3.1E-2.8, Permapol® L56086 are encompassedby the disclosure of U.S. Pat. No. 6,172,179.

A thiol-terminated polythioether prepolymer can comprise athiol-terminated polythioether prepolymer comprising at least one moietyhaving the structure of Formula (2):

—R¹—[S—(CH₂)₂—O—(R²—O—)_(m)(CH₂)₂—S—R¹]_(n)—  (2)

-   -   where,        -   each R¹ can be independently selected from a C₂₋₁₀            n-alkanediyl group, a C₃₋₆ branched alkanediyl group, a C₆₋₈            cycloalkanediyl group, a C₆₋₁₀ alkanecycloalkanediyl group,            a divalent heterocyclic group, and a            —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)— group, wherein each R³            comprises hydrogen or methyl;        -   each R² can be independently selected from a C₂₋₁₀            n-alkanediyl group, a C₃₋₆ branched alkanediyl group, a C₆₋₈            cycloalkanediyl group, a C₆₋₁₄ alkanecycloalkanediyl group,            a divalent heterocyclic group, and a            —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group;        -   each X can independently be selected from O, S, S—S, and NR,            wherein R can be selected from hydrogen and methyl;        -   m ranges from 0 to 50;        -   n is an integer ranging from 1 to 60;        -   p is an integer ranging from 2 to 6;        -   q is an integer ranging from 1 to 5; and        -   r is an integer ranging from 2 to 10.

In moieties of Formula (2), R¹ can be —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—,wherein each X can independently be selected from O and S. In moietiesof Formula (2), R¹ can be —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, each X can beO or each X can be S.

In moieties of Formula (2), R¹ can be —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)—,wherein each X can independently be selected from O and S. In moietiesof Formula (2), R¹ can be —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)—, each X can be Oor each X can be S.

In moieties of Formula (2), R¹ can be —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)—,where p can be 2, X can be O, q can be 2, r can be 2, R² can beethanediyl, m can be 2, and n can be 9.

In moieties of Formula (2), each R¹ can be derived from1,8-dimercapto-3,6-dioxaoctane (DMDO), each R¹ can be derived fromdimercaptodiethylsulfide (DMDS), or a combination thereof.

In moieties of Formula (2), each m can independently be an integer from1 to 3. Each m can be the same and can be 1, 2, or 3.

In moieties of Formula (2), n can be an integer from 1 to 30, an integerfrom 1 to 20, an integer from 1 to 10, or an integer from 1 to 5. Inaddition, n may be any integer from 1 to 60.

In moieties of Formula (2), each p can independently be 2, 3, 4, 5, and6. Each p can be the same and can be 2, 3, 4, 5, or 6.

In moieties of Formula (2), each q can independently be 1, 2, 3, 4, or5. Each q can be the same and can be 1, 2, 3, 4, or 5.

In moieties of Formula (2), each r can independently be 2, 3, 4, 5, 6,7, 8, 9, or 10.

In moieties of Formula (2), each r can be the same and can be 2, 3, 4,5, 6, 7, 8, 9, or 10.

In moieties of Formula (2), each r can independently be an integer from2 to 4, from 2 to 6, or from 2 to 8.

In moieties of Formula (2), each R² can independently be a C₂₋₁₀n-alkanediyl group, a C₃₋₆ branched alkanediyl group, or a—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group.

In moieties of Formula (2), each R² can independently comprise a C₂₋₁₀n-alkanediyl group.

In moieties of Formula (2), each R² can independently be a—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each X can be O or S.

A thiol-terminated polythioether prepolymer can comprise athiol-terminated polythioether prepolymer of Formula (2a), athiol-terminated polythioether prepolymer of Formula (2b), or acombination thereof:

HS—R¹—[S—(CH₂)₂—O—(R²—O)_(m)(CH₂)₂—S—R¹—]_(n)SH  (2a)

{HS—R—[S—(CH₂)₂—O—(R²—O—)_(m)(CH₂)₂—S—R¹—]_(n)S-V′-}_(z)B  (2b)

-   -   wherein,        -   each R¹ can independently be selected from C₂₋₁₀ alkanediyl,            C₆₋₈ cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, C₅₋₈            heterocycloalkanediyl, and —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—,            wherein,            -   p is an integer from 2 to 6;            -   q is an integer from 1 to 5;            -   r is an integer from 2 to 10;            -   each R³ independently be selected from hydrogen and                methyl; and            -   each X can independently be selected from O, S, S—S, and                NR, wherein R can be selected from hydrogen and methyl;        -   each R² can independently be selected from C₁₋₁₀ alkanediyl,            C₆₋₈ cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, and            —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, wherein p, q, r, R³, and X            are as defined as for R¹;        -   m is an integer from 0 to 50;        -   n is an integer from 1 to 60;        -   B represents a core of a z-valent, polyfunctionalizing agent            B(-V)_(z) wherein,            -   z is an integer from 3 to 6; and            -   each V is a moiety comprising a terminal group reactive                with a thiol; and        -   each -V′- is derived from the reaction of -V with a thiol.

In prepolymers of Formula (2a) and Formula (2b), R¹ can be—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)—, where p can be 2, X can be O, q can be 2,r can be 2, R² can be ethanediyl, m can be 2, and n can be 9.

In prepolymers of Formula (2a) and Formula (2b), R¹ can comprise C₂₋₆alkanediyl or —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—.

In prepolymers of Formula (2a) and Formula (2b), R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, X can be O or X can be S.

In prepolymers of Formula (2a) and Formula (2b), where R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, p can be 2, r can be 2, q can be 1, andX can be S; or wherein p can be 2, q can be 2, r can be 2, and X can beO; or p can be 2, r can be 2, q can be 1, and X can be O.

In prepolymers of Formula (2a) and Formula (2b), R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, and each R³ can be hydrogen or at leastone R³ can be methyl.

In prepolymers of Formula (2a) and Formula (2b), each R¹ can be thesame, or at least one R1 can be different.

In prepolymers of Formula (2a) and Formula (2b), each m can beindependently an integer from 1 to 3. Each m can be the same and is canbe 1, 2, or 3.

In prepolymers of Formula (2a) and Formula (2b), n can be an integerfrom 1 to 30, an integer from 1 to 20, an integer from 1 to 10, or aninteger from 1 to 5. The variable n may be any integer from 1 to 60.

In prepolymers of Formula (2a) and Formula (2b), each p canindependently be 2, 3, 4, 5, and 6. Each p can be the same and can be 2,3, 4, 5, or 6.

In prepolymers of Formula (2a) and Formula (2b), each q canindependently be 1, 2, 3, 4, or 5. Each q can be the same and can be 1,2, 3, 4, or 5.

In prepolymers of Formula (2a) and Formula (2b), each r canindependently be 2, 3, 4, 5, 6, 7, 8, 9, or 10.

In prepolymers of Formula (2a) and Formula (2b), each r can be the sameand can be 2, 3, 4, 5, 6, 7, 8, 9, or 10.

In prepolymers of Formula (2a) and Formula (2b), each r canindependently be an integer from 2 to 4, from 2 to 6, or from 2 to 8.

A thiol-terminated polythioether prepolymer can comprise a moiety havingthe structure of Formula (2c):

—S—R¹—[S-A-S—R¹-]_(n)—S—  (2c)

-   -   wherein,        -   n is an integer from 1 to 60;        -   each R¹ is independently selected from C₂₋₁₀ alkanediyl,            C₆₋₈ cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, C₅₋₈            heterocycloalkanediyl, and —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—,            wherein,            -   p is an integer from 2 to 6;            -   q is an integer from 1 to 5;            -   r is an integer from 2 to 10;            -   each R³ is independently selected from hydrogen and                methyl; and            -   each X is independently selected from O, S, and NR,                wherein R is selected from hydrogen and methyl; and        -   each A is independently a moiety derived from a polyvinyl            ether of Formula (3) and a polyalkenyl polyfunctionalizing            agent of Formula (4):

CH₂═CH—O—(R²—O)_(m)—CH═CH₂  (3)

B(—R⁷⁰—CH═CH₂)_(z)  (4)

-   -   -   wherein,            -   m is an integer from 0 to 50;            -   each R² is independently selected from C₁₋₁₀ alkanediyl,                C₆₋₈ cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, and                —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, wherein p, q, r, R³,                and X are as defined as for R¹;            -   B represents a core of a z-valent, polyalkenyl                polyfunctionalizing agent B(—R⁷⁰—CH═CH₂)_(z) wherein,            -   z is an integer from 3 to 6; and            -   each R⁷⁰ is independently selected from C₁₋₁₀                alkanediyl, C₁₋₁₀ heteroalkanediyl, substituted C₁₋₁₀                alkanediyl, and substituted C₁₋₁₀ heteroalkanediyl.

In moieties of Formula (2c), R¹ can be C₂₋₁₀ alkanediyl.

In moieties of Formula (2c), R¹ can be —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—.

In moieties of Formula (2c), X can be selected from O and S, and thus—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)— in Formula (2c) can be—[(CHR³)_(p)—O—]_(q)(CHR³)_(r)— or —[(CHR³)_(p)—S—]_(q)(CHR³)_(r)—. Pand r can be equal, such as where p and r can be both two.

In moieties of Formula (2c), R¹ can be selected from C₂₋₆ alkanediyl and—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—.

In moieties of Formula (2c), R¹ can be —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—,and X can be O, or X can be S.

In moieties of Formula (2c) where R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, p can be 2, r can be 2, q can be 1, andX can be S; or p can be 2, q can be 2, r can be 2, and X can be O; or pcan be 2, r can be 2, q can be 1, and X can be O.

In moieties of Formula (2c) where R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, each R³ can be hydrogen, or at leastone R³ can be methyl.

In moieties of Formula (2c), R¹ can be —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)—wherein each X can independently be selected from O and S. In moietiesof Formula (2c), R¹ can be —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— each X can be Oor each X can be S.

In moieties of Formula (2c), R¹ can be —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)—,where p can be 2, X can be O, q can be 2, r can be 2, R² can beethanediyl, m can be 2, and n can be 9.

In moieties of Formula (2c), each R¹ can be derived from1,8-dimercapto-3,6-dioxaoctane (DMDO;2,2-(ethane-1,2-diylbis(sulfanyl))bis(ethan-1-thiol)), or each R¹ can bederived from dimercaptodiethylsulfide (DMDS;2,2′-thiobis(ethan-1-thiol)), and combinations thereof.

In moieties of Formula (2c), each p can independently be selected from2, 3, 4, 5, and 6. Each p can be the same and can be 2, 3, 4, 5, or 6.

In moieties of Formula (2c) each q can independently be 1, 2, 3, 4, or5. Each q can be the same and can be 1, 2, 3, 4, or 5.

In moieties of Formula (2c), each r can independently be 2, 3, 4, 5, 6,7, 8, 9, or 10. Each r can be the same and can be 2, 3, 4, 5, 6, 7, 8,9, or 10.

In moieties of Formula (2c), each r can independently be an integer from2 to 4, from 2 to 6, or from 2 to 8.

In moieties of Formula (2c), each A can be derived from a polyvinylether such as a divinyl ether. A divinyl ether can comprise a divinylether having the structure of Formula (3). Divinyl ethers are alsoreferred to as bis(alkenyl)ethers.

In divinyl ethers of Formula (3), m can be an integer from 0 to 50, suchas from 0 to 40, from 0 to 20, from 0 to 10, from 1 to 50, from 1 to 40,from 1 to 20, from 1 to 10, from 2 to 50, from 2 to 40, from 2 to 20, orfrom 2 to 10.

In divinyl ethers of Formula (3), each R² can independently be selectedfrom a C₂₋₁₀ n-alkanediyl group, a C₃₋₆ branched alkanediyl group, and a—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group.

In divinyl ethers of Formula (3), each R² can independently be a C₂₋₁₀n-alkanediyl group, such as methanediyl, ethanediyl, n-propanediyl, orn-butanediyl.

In divinyl ethers of Formula (3), each R² can independently comprise a—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each X can be O or S.

In divinyl ethers of Formula (3), each R² can independently comprise a—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group.

In divinyl ethers of Formula (3), each m can be independently an integerfrom 1 to 3. Each m can be the same and is can be 1, 2, or 3.

In divinyl ethers of Formula (3), each R² can independently be selectedfrom a C₂₋₁₀ n-alkanediyl group, a C₃₋₆ branched alkanediyl group, and a—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group.

In divinyl ethers of Formula (3), each R² can independently be a C₂₋₁₀n-alkanediyl group.

In divinyl ethers of Formula (3), each R² can independently be a—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each X can be O or S.

In divinyl ethers of Formula (3), each R² can independently be a—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each X can be O or S, andeach p can independently be 2, 3, 4, 5, and 6.

In divinyl ethers of Formula (3), each p can be the same and can be 2,3, 4, 5, or 6.

In divinyl ethers of Formula (3), each R² can independently be a—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each X can be O or S, andeach q can independently be 1, 2, 3, 4, or 5.

In divinyl ethers of Formula (3), each q can be the same and can be 1,2, 3, 4, or 5.

In divinyl ethers of Formula (3), each R² can independently be a—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each X can be O or S, andeach r can independently be 2, 3, 4, 5, 6, 7, 8, 9, or 10. In divinylethers of Formula (3), each r can be the same and can be 2, 3, 4, 5, 6,7, 8, 9, or 10. In divinyl ethers of Formula (3), each r canindependently be an integer from 2 to 4, from 2 to 6, or from 2 to 8.

In divinyl ethers of Formula (3), each R² can independently be a—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each X can be O or S, andeach r can independently be 2, 3, 4, 5, 6, 7, 8, 9, or 10. In divinylethers of Formula (3), each r can be the same and can be 2, 3, 4, 5, 6,7, 8, 9, or 10. In divinyl ethers of Formula (3), each r canindependently be an integer from 2 to 4, from 2 to 6, or from 2 to 8.

Examples of suitable divinyl ethers include ethylene glycol divinylether (EG-DVE butanediol divinyl ether (BD-DVE) hexanediol divinyl ether(HD-DVE), diethylene glycol divinyl ether (DEG-DVE), triethylene glycoldivinyl ether tetraethylene glycol divinyl ether cyclohexanedimethanoldivinyl ether, polytetrahydrofuryl divinyl ether; and combinations ofany of the foregoing.

A divinyl ether can comprise a sulfur-containing divinyl ether. Examplesof suitable sulfur-containing divinyl ethers are disclosed, for example,in PCT International Publication No. WO 2018/085650, which isincorporated by reference in its entirety.

In moieties of Formula (2c) each A can independently be derived from apolyalkenyl polyfunctionalizing agent. A polalkenyl polyfunctionalizingagent can have the structure of Formula (4), where z can be 3, 4, 5, or6.

In polyalkenyl polyfunctionalizing agents of Formula (4), each R⁷⁰ canindependently be elected from C₁₋₁₀ alkanediyl, each A can independentlybe selected from C₁₋₁₀ heteroalkanediyl, each A can independently beselected from substituted C₁₋₁₀ alkanediyl, or each A can independentlybe selected from substituted C₁₋₁₀ heteroalkanediyl. The one or moresubstituent groups can be selected from, for example, —OH, ═O, C₁₋₄alkyl, and C₁₋₄ alkoxy. The one or more heteroatoms can be selectedfrom, for example, O, S, and a combination thereof.

Examples of suitable polyalkenyl polyfunctionalizing agents includetriallyl cyanurate (TAC), triallylisocyanurate (TAIC),1,3,5-triallyl-1,3,5-triazinane-2,4,6-trione),1,3-bis(2-methylallyl)-6-methylene-5-(2-oxopropyl)-1,3,5-triazinone-2,4-dione,tris(allyloxy)methane, pentaerythritol triallyl ether,1-(allyloxy)-2,2-bis((allyloxy)methyl)butane,2-prop-2-ethoxy-1,3,5-tris(prop-2-enyl)benzene,1,3,5-tris(prop-2-enyl)-1,3,5-triazinane-2,4-dione, and1,3,5-tris(2-methylallyl)-1,3,5-triazinane-2,4,6-trione,1,2,4-trivinylcyclohexane, and combinations of any of the foregoing.

In moieties of Formula (2c) the molar ratio of moieties derived from adivinyl ether to moieties derived from a polyalkenyl polyfunctionalizingagent can be, for example, from 0.9 mol % to 0.999 mol %, from 0.95 mol% to 0.99 mol %, or from 0.96 mol % to 0.99 mol %.

In moieties of Formula (2c), each R¹ can be —(CH₂)₂—O—(CH₂)₂—O—(CH₂)₂—;each R² can be —(CH₂)₂—; and m can be an integer from 1 to 4.

In moieties of Formula (2c), R² can be derived from a divinyl ether sucha diethylene glycol divinyl ether, a polyalkenyl polyfunctionalizingagent such as triallyl cyanurate, or a combination thereof.

In polythioether prepolymers of Formula (2c), each A can independentlybe selected from a moiety of Formula (3a) and a moiety of Formula (4a):

—(CH₂)₂—O—(R²—O)_(m)—(CH₂)₂ ⁻  (3a)

B{-R⁷⁰—(CH₂)₂—}₂{—R⁷⁰—(CH₂)₂—S—[—R¹—S-A-S—S_(u)—R¹—SH}_(z-2)  (4a)

where m, R¹, R², R⁷⁰, A, n, and z are defined as in Formula (2c),Formula (3) and Formula (4).

In moieties of Formula (2c),

-   -   each R¹ can be —(CH₂)₂—O—(CH₂)₂—O—(CH₂)₂—;    -   each R² can be —(CH₂)₂—;    -   m can bean integer from 1 to 4; and    -   the polyfunctionalizing agent B(—R⁷⁰—CH═CH₂)_(z) comprises        triallyl cyanurate where z is 3 and each R⁷⁰ is —O—CH₂—CH═CH₂.

Polythioether prepolymers comprising a moiety of Formula (2c) can bethiol-terminated.

A thiol-terminated polythioether prepolymer can comprise athiol-terminated polythioether prepolymer of Formula (2d):

HS—R¹—[S-A-S—R¹—]_(n)—SH  (2d)

-   -   wherein,        -   n is an integer from 1 to 60;        -   each R¹ is independently selected from C₂₋₁₀ alkanediyl,            C₆₋₈ cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, C₅₋₈            heterocycloalkanediyl, and —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—,            wherein,            -   p is an integer from 2 to 6;            -   q is an integer from 1 to 5;            -   r is an integer from 2 to 10;            -   each R³ is independently selected from hydrogen and                methyl; and            -   each X is independently selected from O, S, and NR,                wherein R is selected from hydrogen and methyl; and        -   each A is independently selected from a moiety derived from            a polyvinyl ether of Formula (3) and a moiety derived from a            polyalkenyl polyfunctionalizing agent of Formula (4):

CH₂═CH—O—(R²—O)_(m)—CH═CH₂  (3)

B(—R⁷⁰—CH═CH₂)_(z)  (4)

-   -   -   wherein,            -   each R² is independently selected from C₁₋₁₀ alkanediyl,                C₆₋₈ cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, and                —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, wherein p, q, r, R³,                and X are as defined as for R¹;            -   m is an integer from 0 to 50;        -   B represents a core of a z-valent, polyalkenyl            polyfunctionalizing agent B(—R⁷⁰—CH═CH₂)_(z) wherein,        -   z is an integer from 3 to 6; and        -   each R⁷⁰ is independently selected from C₁₋₁₀ alkanediyl,            C₁₋₁₀ heteroalkanediyl, substituted C₁₋₁₀ alkanediyl, and            substituted C₁₋₁₀ heteroalkanediyl.

In thiol-terminated polythioether prepolymers of Formula (2d), R¹ can beC₂₋₁₀ alkanediyl.

In thiol-terminated polythioether prepolymers of Formula (2d), R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—.

In thiol-terminated polythioether prepolymers of Formula (2d), X can beselected from O and S, and thus —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)— inFormula (2d) can be —[(CHR³)_(p)—O—]_(q)(CHR³)_(r)— or—[(CHR³)_(p)—S—]_(q)(CHR³)_(r)—. P and r can be equal, such as where pand r can be both two.

In thiol-terminated polythioether prepolymers of Formula (2d), R¹ can beselected from C₂₋₆ alkanediyl and —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—.

In thiol-terminated polythioether prepolymers of Formula (2d), R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, and X can be O, or X can be S.

In thiol-terminated polythioether prepolymers of Formula (2d), where R¹can be —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, p can be 2, r can be 2, q can be1, and X can be S; or p can be 2, q can be 2, r can be 2, and X can beO; or p can be 2, r can be 2, q can be 1, and X can be O.

In thiol-terminated polythioether prepolymers of Formula (2d), where R¹can be —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, each R³ can be hydrogen, or atleast one R³ can be methyl.

In thiol-terminated polythioether prepolymers of Formula (2d), R¹ can be—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— wherein each X can independently beselected from O and S. In thiol-terminated polythioether prepolymers ofFormula (2d), R¹ can be —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— each X can be O oreach X can be S.

In thiol-terminated polythioether prepolymers of Formula (2d), R¹ can be—[(CH₂)_(p)—X—]_(q)(CH₂)_(r)—, where p can be 2, X can be O, q can be 2,r can be 2, R² can be ethanediyl, m can be 2, and n can be 9.

In thiol-terminated polythioether prepolymers of Formula (2d), each R¹can be derived from 1,8-dimercapto-3,6-dioxaoctane (DMDO;2,2-(ethane-1,2-diylbis(sulfanyl))bis(ethan-1-thiol)), or each R¹ can bederived from dimercaptodiethylsulfide (DMDS;2,2′-thiobis(ethan-1-thiol)), and combinations thereof.

In thiol-terminated polythioether prepolymers of Formula (2d), each pcan independently be selected from 2, 3, 4, 5, and 6. Each p can be thesame and can be 2, 3, 4, 5, or 6.

In thiol-terminated polythioether prepolymers of Formula (2d), each qcan independently be 1, 2, 3, 4, or 5. Each q can be the same and can be1, 2, 3, 4, or 5.

In thiol-terminated polythioether prepolymers of Formula (2d), each rcan independently be 2, 3, 4, 5, 6, 7, 8, 9, or 10. Each r can be thesame and can be 2, 3, 4, 5, 6, 7, 8, 9, or 10.

In thiol-terminated polythioether prepolymers of Formula (2d), each rcan independently be an integer from 2 to 4, from 2 to 6, or from 2 to8.

In thiol-terminated polythioether prepolymers of Formula (2d), each Acan independently be selected from a moiety of Formula (3a) and a moietyof Formula (4a):

—(CH₂)₂—O—(R²—O)_(m)—(CH₂)₂—  (3a)

B{-R⁷⁰—(CH₂)₂—}₂{R⁷⁰—(CH₂)₂—S—[—R¹—S-A-S—]—R—SH}_(z-2)  (4a)

where m, R¹, R², R⁷⁰, A, n1, and z are defined as in Formula (3) andFormula (4).

In thiol-terminated polythioether prepolymers of Formula (2d) the molarratio of moieties derived from a divinyl ether to moieties derived froma polyalkenyl polyfunctionalizing agent can be, for example, of 200:1,150:1, 100:1, 50:1, or 25:1.

Polythioethers comprising a moiety of Formula (2) or Formula (2c) can bealkenyl-terminated.

A thiol-terminated polythioether prepolymer can comprise, for example, athiol-terminated polythioether prepolymer of Formula (2e):

CH₂═CH-A¹-(CH₂)₂—S—R¹—[S-A-S—R¹-]_(n)—S—(CH₂)₂-A¹-CH═CH₂  (2e)

-   -   wherein,        -   n is an integer from 1 to 60;        -   each R¹ is independently selected from C₂₋₁₀ alkanediyl,            C₆₋₈ cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, C₅₋₈            heterocycloalkanediyl, and —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—,            wherein,            -   p is an integer from 2 to 6;            -   q is an integer from 1 to 5;            -   r is an integer from 2 to 10;            -   each R³ is independently selected from hydrogen and                methyl; and            -   each X is independently selected from O, S, and NR,                wherein R is selected from hydrogen and methyl; and        -   each A is independently selected from a moiety derived from            a polyvinyl ether of Formula (3) and a moiety derived from a            polyalkenyl polyfunctionalizing agent of Formula (4):

CH₂═CH—O—(R²—O)_(m)—CH═CH₂  (3)

B(—R⁷⁰—CH═CH₂)_(z)  (4)

-   -   -   wherein,            -   each R² is independently selected from C₁₋₁₀ alkanediyl,                C₆₋₈ cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, and                —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, wherein p, q, r, R³,                and X are as defined as for R¹;            -   m is an integer from 0 to 50;        -   each A¹ is independently a moiety of Formula (3d):

—O—(R²—O)_(m)—  (3d)

-   -   -   -   where m and each R² are defined as in Formula (3);

        -   B represents a core of a z-valent, polyalkenyl            polyfunctionalizing agent B(—R⁷⁰—CH═CH₂)_(z) wherein,

        -   z is an integer from 3 to 6; and

        -   each R⁷⁰ is independently selected from C₁₋₁₀ alkanediyl,            C₁₋₁₀ heteroalkanediyl, substituted C₁₋₁₀ alkanediyl, and            substituted C₁₋₁₀ heteroalkanediyl.

In alkenyl-terminated polythioether prepolymers of Formula (2e), R¹ canbe C₂₋₁₀ alkanediyl.

In alkenyl-terminated polythioether prepolymers of Formula (2e), R¹ canbe —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—.

In alkenyl-terminated polythioether prepolymers of Formula (2e), X canbe selected from O and S, and thus —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)— inFormula (2e) can be —[(CHR³)_(p)—O—]_(q)(CHR³)_(r)— or—[(CHR³)_(p)—S—]_(q)(CHR³)_(r)—. P and r can be equal, such as where pand r can be both two.

In alkenyl-terminated polythioether prepolymers of Formula (2e), R¹ canbe selected from C₂₋₆ alkanediyl and —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—.

In alkenyl-terminated polythioether prepolymers of Formula (2e), R¹ canbe —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, and X can be O, or X can be S.

In alkenyl-terminated polythioether prepolymers of Formula (2e), whereR¹ can be —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, p can be 2, r can be 2, q canbe 1, and X can be S; or p can be 2, q can be 2, r can be 2, and X canbe O; or p can be 2, r can be 2, q can be 1, and X can be O.

In alkenyl-terminated polythioether prepolymers of Formula (2e), whereR¹ can be —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, each R³ can be hydrogen, orat least one R³ can be methyl.

In alkenyl-terminated polythioether prepolymers of Formula (2e), R¹ canbe —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— wherein each X can independently beselected from O and S. In alkenyl-terminated polythioether prepolymersof Formula (2e), R¹ can be —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— each X can be Oor each X can be S.

In alkenyl-terminated polythioether prepolymers of Formula (2e), R¹ canbe —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)—, where p can be 2, X can be O, q can be2, r can be 2, R² can be ethanediyl, m can be 2, and n can be 9.

In alkenyl-terminated polythioether prepolymers of Formula (2e), each R¹can be derived from 1,8-dimercapto-3,6-dioxaoctane (DMDO;2,2-(ethane-1,2-diylbis(sulfanyl))bis(ethan-1-thiol)), or each R¹ can bederived from dimercaptodiethylsulfide (DMDS;2,2′-thiobis(ethan-1-thiol)), and combinations thereof.

In alkenyl-terminated polythioether prepolymers of Formula (2e), each pcan independently be selected from 2, 3, 4, 5, and 6. Each p can be thesame and can be 2, 3, 4, 5, or 6.

In alkenyl-terminated polythioether prepolymers of Formula (2e), each qcan independently be 1, 2, 3, 4, or 5. Each q can be the same and can be1, 2, 3, 4, or 5.

In alkenyl-terminated polythioether prepolymers of Formula (2e), each rcan independently be 2, 3, 4, 5, 6, 7, 8, 9, or 10. Each r can be thesame and can be 2, 3, 4, 5, 6, 7, 8, 9, or 10.

In alkenyl-terminated polythioether prepolymers of Formula (2a), each rcan independently be an integer from 2 to 4, from 2 to 6, or from 2 to8.

In alkenyl-terminated polythioether prepolymers of Formula (2e), each Acan independently be selected from a moiety of Formula (3a) and a moietyof Formula (4b):

—(CH₂)₂—O—(R²—O)_(m)—(CH₂)₂—  (3a)

B{-R⁷⁰—(CH₂)₂—}2{—R⁷⁰—(CH₂)₂—S—[—R¹—S-A-S-]_(n1)-R¹—S—(CH₂)₂-A¹-CH═CH₂}_(z-2)  (4b)

where m, R¹, R², R⁷⁰, A, n1, and z are defined as in Formula (3) andFormula (4).

In alkenyl-terminated polythioether prepolymers of Formula (2e) themolar ratio of moieties derived from a divinyl ether to moieties derivedfrom a polyalkenyl polyfunctionalizing agent can be, for example, of200:1, 150:1, 100:1, 50:1, or 25:1.

Various methods can be used to prepare thiol-terminated polythioetherprepolymers of Formula (2a) and Formula (2b). Examples of suitablethiol-terminated polythioether prepolymers, and methods for theirproduction, are described in U.S. Pat. No. 6,172,179. Suchthiol-terminated polythioether prepolymers may be difunctional, that is,linear prepolymers having two terminal thiol groups, or can bepolyfunctional, that is, branched prepolymers having three or moreterminal thiol-groups. In practice, thiol-terminated polythioetherprepolymers are a combination of prepolymers having complex structureshaving an average thiol-functionality, for example, from 2.1 to 2.9.

A thiol-terminated polythioether prepolymer may comprise a combinationof different thiol-terminated polythioether prepolymers and thethiol-terminated polythioether prepolymers may have the same ordifferent functionality. A thiol-terminated polythioether prepolymer orcombination of thiol-terminated polythioether prepolymers can have anaverage functionality, for example, from 2 to 6, from 2 to 4, from 2 to3, from 2.05 to 2.8, or from 2.05 to 2.5. For example, athiol-terminated polythioether prepolymer can comprise a difunctionalthiol-terminated polythioether prepolymer, a trifunctionalthiol-terminated polythioether prepolymer, or a combination thereof.

A thiol-terminated polythioether prepolymer can be prepared by reactinga polythiol and a diene such as a divinyl ether, and the respectiveamounts of the reactants used to prepare the polythioether prepolymerscan be chosen to yield terminal thiol groups. Thus, in some cases, (nor >n, such as n+1) moles of a polythiol, such as a dithiol or a mixtureof at least two different dithiols and 0.05 moles to 1 moles, such asfrom 0.1 moles to 0.8 moles, of a thiol-terminated polyfunctionalizingagent and/or an alkenyl-terminated polyfunctionalizing agent may bereacted with (n) moles of a diene, such as a divinyl ether, or acombination of at least two different dienes, such as a combination oftwo different divinyl ethers. A thiol-terminated polyfunctionalizingagent can be present in the reaction mixture in an amount sufficient toprovide a thiol-terminated polythioether prepolymer having an averagethiol functionality, for example, from 2.05 to 3, such as from 2.1 to2.8, or from 2.1 to 2.6.

A reaction used to prepare a thiol-terminated polythioether prepolymermay be catalyzed by a free radical catalyst. Suitable free radicalcatalysts include azo compounds, for example, azobisnitrile compoundssuch as azo(bis)isobutyronitrile (AIBN); organic peroxides, such asbenzoyl peroxide and tert-butyl peroxide; and inorganic peroxides, suchas hydrogen peroxide. The reaction can also be effected by irradiationwith ultraviolet light either with or without a radicalinitiator/photosensitizer. Ionic catalysis methods, using eitherinorganic or organic bases, e.g., triethylamine, may also be used.

Suitable thiol-terminated polythioether prepolymers may be produced byreacting a divinyl ether or combination of divinyl ethers with an excessof dithiol or combination of dithiols.

A thiol-terminated polythioether prepolymer can comprise the reactionproduct of reactants comprising:

-   -   (a) a dithiol of Formula (5):

HS—R¹—SH  (5)

-   -   -   wherein,            -   R¹ is selected from C₂₋₆ alkanediyl, C₆₋₈                cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl, C₅₋₈                heterocycloalkanediyl, and                —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—;        -   wherein,            -   each R³ is independently selected from hydrogen and                methyl;            -   each X is independently selected from —O—, —S—, —S—S—,                and —NR— wherein R is selected from hydrogen and methyl;        -   p is an integer from 2 to 6;        -   q is an integer from 1 to 5; and        -   r is an integer from 2 to 10; and

    -   (b) a bis(alkenyl) ether of Formula (3):

CH₂═CH—O—(R²—O—)_(m)CH═CH₂  (3)

-   -   -   wherein,            -   each R² is independently selected from C₁₋₁₀ alkanediyl,                C₆₋₈ cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, and                —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, wherein p, q, r, R³,                and X are as defined above; and        -   m is an integer from 0 to 50.

The reactants can further comprise (c) a polyfunctional compound such asa polyakenyl polyfunctionalizing agent such as a polyfunctional compoundB(-V)_(z), where B, -V, and z are defined as for Formula (2b).

In dithiols of Formula (5), R¹ can be —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—.

In dithiols of Formula (5), R¹ can be —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—and X can be selected from O and S, and thus—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)— in Formula (5) can be—[(CHR³)_(p)—O—]_(q)(CHR³)_(r)— or —[(CHR³)_(p)—S—]_(q)(CHR³)_(r)—. Pand r can be equal, such as where p and r can be both two.

In dithiols of Formula (5), R¹ can comprise C₂₋₆ alkanediyl and—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—.

In dithiols of Formula (5), R¹ can be —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—,and X can be O, or X can be S.

In dithiols of Formula (5) where R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, p can be 2, r can be 2, q can be 1, andX can be S; or p can be 2, q can be 2, r can be 2, and X can be O; or pcan be 2, r can be 2, q can be 1, and X can be O.

In dithiols of Formula (5) where R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, each R³ can be hydrogen, or at leastone R³ can be methyl.

In dithiols of Formula (5), each R¹ can be derived from1,8-dimercapto-3,6-dioxaoctane (DMDO;2,2-(ethane-1,2-diylbis(sulfanyl))bis(ethan-1-thiol)), or each R¹ can bederived from dimercaptodiethylsulfide (DMDS;2,2′-thiobis(ethan-1-thiol)), and combinations thereof.

In dithiols of Formula (5), where R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, each p can independently comprise 2, 3,4, 5, and 6. Each p can be the same and can be 2, 3, 4, 5, or 6.

In dithiols of Formula (5), where R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, each q can independently be 1, 2, 3, 4,or 5. Each q can be the same and can be 1, 2, 3, 4, or 5.

In dithiols of Formula (5), where R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, each r can independently be 2, 3, 4, 5,6, 7, 8, 9, or 10, Each r can be the same and can be 2, 3, 4, 5, 6, 7,8, 9, or 10.

In dithiols of Formula (5), where R¹ can be—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, each r can independently be an integerfrom 2 to 4, from 2 to 6, or from 2 to 8.

In bis(alkenyl) ethers of Formula (3), each m can be independently aninteger from 1 to 3. Each m can be the same and is can be 1, 2, or 3.

In bis(alkenyl) ethers of Formula (3), each R² can independentlycomprise a C₂₋₁₀ n-alkanediyl group, a C₃₋₆ branched alkanediyl group,or a —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group.

In bis(alkenyl) ethers of Formula (3), each R² can independentlycomprise a C₂₋₁₀ n-alkanediyl group.

In bis(alkenyl) ethers of Formula (3), each R² can independentlycomprise a —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each X can be O orS.

In bis(alkenyl) ethers of Formula (3), each R² can independentlycomprise a —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each X can be O orS, and each p can independently be 2, 3, 4, 5, and 6.

In bis(alkenyl) ethers of Formula (3), each R² can independentlycomprise a —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each p can be thesame and can be 2, 3, 4, 5, or 6.

In bis(alkenyl) ethers of Formula (3), each R² can independentlycomprise a —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each X can be O orS, and each q can independently be 1, 2, 3, 4, or 5.

In bis(alkenyl) ethers of Formula (3), each R² can independentlycomprise a —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each q can be thesame and can be 1, 2, 3, 4, or 5.

In bis(alkenyl) ethers of Formula (3), each R² can independentlycomprise a —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)— group, where each X can be O orS, and each r can independently be 2, 3, 4, 5, 6, 7, 8, 9, or 10,

In bis(alkenyl) ethers of Formula (3), each r can be the same and can be2, 3, 4, 5, 6, 7, 8, 9, or 10. In bis(alkenyl) ethers of Formula (3),each r can independently be an integer from 2 to 4, from 2 to 6, or from2 to 8.

Dithiols suitable for use in preparing thiol-terminated polythioetherprepolymers include those having the structure of Formula (5):

HS—R¹—SH  (5)

wherein, R¹ can be C₂₋₆ alkanediyl, C₆₋₈ cycloalkanediyl, C₆₋₁₀alkanecycloalkanediyl, C₅₋₈ heterocycloalkanediyl, or—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—; wherein, each R³ can independently canbe hydrogen or methyl; each X can independently be O, S, —S—S—, or NRwherein R can be hydrogen or methyl; p is an integer from 2 to 6; q isan integer from 1 to 5; and r is an integer from 2 to 10.

Examples of suitable dithiols include 1,2-ethanedithiol,1,2-propanedithiol, 1,3-propanedithiol, 1,3-butanedithiol,1,4-butanedithiol, 2,3-butanedithiol, 1,3-pentanedithiol,1,5-pentanedithiol, 1,6-hexanedithiol, 1,3-dimercapto-3-methylbutane,dipentenedimercaptan, ethylcyclohexyldithiol (ECHDT),dimercaptodiethylsulfide, methyl-substituted dimercaptodiethylsulfide,dimethyl-substituted dimercaptodiethylsulfide, dimercaptodioxaoctane,1,5-dimercapto-3-oxapentane, and a combination of any of the foregoing.

A dithiol may have one or more pendent groups comprising a lower (e.g.,C₁₋₆) alkyl group, a lower alkoxy group, or a hydroxyl group. Suitablealkyl pendent groups include, for example, C₁₋₆ linear alkyl, C₃₋₆branched alkyl, cyclopentyl, and cyclohexyl.

Other examples of suitable dithiols include dimercaptodiethylsulfide(DMDS) (in Formula (5), R¹ is —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)—, wherein pis 2, r is 2, q is 1, and X is S); dimercaptodioxaoctane (DMDO) (inFormula (5), R¹ is —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)—, wherein p is 2, q is2, r is 2, and X is O); and 1,5-dimercapto-3-oxapentane (in Formula (5),R¹ is —[(CH₂)_(p)—X—]_(q)(CH₂)_(r)—, wherein p is 2, r is 2, q is 1, andX is O). It is also possible to use dithiols that include bothheteroatoms in the carbon backbone and pendent alkyl groups, such asmethyl groups. Such dithiols include, for example, methyl-substitutedDMDS, such as HS—CH₂CH(CH₃)—S—CH₂CH₂—SH, HS—CH(CH₃)CH₂—S—CH₂CH₂—SH anddimethyl substituted DMDS, such as HS—CH₂CH(CH₃)—S—CH(CH₃)CH₂—SH andHS—CH(CH₃)CH₂—S—CH₂CH(CH₃)—SH.

Suitable bis(alkenyl) ethers for preparing thiol-terminatedpolythioether prepolymers include, for example, bis(alkenyl) ethers ofFormula (3):

CH₂═CH—O—(R²—O—)_(m)CH═CH₂  (3)

where each R² can independently be C₁₋₁₀ alkanediyl, C₆₋₈cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, or—[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, where each R³ can independentlycomprise hydrogen or methyl; each X can independently comprise O, S,—S—S—, or NR wherein R can be hydrogen or methyl; p can be an integerfrom 2 to 6; q can be an integer from 1 to 5; and r can be an integerfrom 2 to 10.

Suitable bis(alkenyl) ethers include, for example, compounds having atleast one oxyalkanediyl group —R²—O—, such as from 1 to 4 oxyalkanediylgroups, i.e., compounds in which m in Formula (3) is an integer rangingfrom 1 to 4. The variable m in Formula (3) can be an integer rangingfrom 2 to 4. It is also possible to employ commercially availabledivinyl ether mixtures that are characterized by a non-integral averagevalue for the number of oxyalkanediyl units per molecule. Thus, m inFormula (3) can also take on rational number values ranging from 0 to10.0, such as from 1.0 to 10.0, from 1.0 to 4.0, or from 2.0 to 4.0.

Examples of suitable bis(alkenyl) ethers include ethylene glycol divinylether (EG-DVE) (R² in Formula (3) is ethanediyl and m is 1), butanedioldivinyl ether (BD-DVE) (R² in Formula (3) is butanediyl and m is 1),hexanediol divinyl ether (HD-DVE) (R² in Formula (3) is hexanediyl and mis 1), diethylene glycol divinyl ether (DEG-DVE) (R² in Formula (3) isethanediyl and m is 2), triethylene glycol divinyl ether (R² in Formula(3) is ethanediyl and m is 3), tetraethylene glycol divinyl ether (R² inFormula (3) is ethanediyl and m is 4), cyclohexanedimethanol divinylether, polytetrahydrofuryl divinyl ether; trivinyl ether monomers, suchas trimethylolpropane trivinyl ether; tetrafunctional ether monomers,such as pentaerythritol tetravinyl ether; and combinations of two ormore such polyvinyl ether monomers. A polyvinyl ether may have one ormore pendent groups which can comprise alkyl groups, hydroxyl groups,alkoxy groups, or amine groups.

Bis(alkenyl) ethers in which R² in Formula (3) is C₃₋₆ branchedalkanediyl may be prepared by reacting a polyhydroxyl compound withacetylene. Examples of divinyl ethers of this type include compounds inwhich R² in Formula (3) is an alkyl-substituted methanediyl group suchas CH(—CH₃), or an alkyl-substituted ethanediyl.

Two or more types of bis(alkenyl) ethers of Formula (3) may be used.Thus, two dithiols of Formula (5) and one divinyl ethers of Formula (3),one dithiol of Formula (5) and two divinyl ethers of Formula (3), twodithiols of Formula (5) and two divinyl ethers of Formula (3), and morethan two compounds of one or both Formula (5) and Formula (3), may beused to produce a variety of thiol-terminated polythioethersprepolymers.

The bis(alkenyl) ethers can comprise, for example, from 20 mole percentto less than 50 mole percent of the reactants used to prepare athiol-terminated polythioether prepolymer, or 30 mole percent to lessthan 50 mole percent.

Relative amounts of dithiols and bis(alkenyl) ethers can be selected toyield polythioether prepolymers having terminal thiol groups. Thus, adithiol of Formula (5) or a mixture of at least two different dithiolsof Formula (5), can be reacted with of a bis(alkenyl) ethers of Formula(3) or a mixture of at least two different bis(alkenyl) ethers ofFormula (3) in relative amounts such that the molar ratio of thiolgroups to alkenyl groups is greater than 1:1, such as from 1.1:1.0 to2.0:1.0.

The reaction between dithiols and bis(alkenyl) ethers and/or polythiolsand bis(alkenyl) ethers may be catalyzed by a free radical catalyst, anionic catalyst, or ultraviolet radiation. Suitable free radicalcatalysts include, for example, azo compounds, for exampleazobisnitriles such as azo(bis)isobutyronitrile (AIBN); organicperoxides such as benzoyl peroxide and tert-butyl peroxide; andinorganic peroxides such as hydrogen peroxide. In certain reactions, thecatalyst does not comprise acidic or basic compounds, and does notproduce acidic or basic compounds upon decomposition. Examples ofsuitable free-radical catalysts include azo-type catalysts, such asVazo®-57 (Du Pont), Vazo®-64 (Du Pont), Vazo®-67 (Du Pont), V-70® (WakoSpecialty Chemicals), and V-65B® (Wako Specialty Chemicals). Examples ofother suitable free-radical catalysts include alkyl peroxides, such astert-butyl peroxide. The reaction may also be effected by irradiationwith ultraviolet light either with or without a cationicphoto-initiating moiety.

Thiol-terminated polythioether prepolymers provided by the presentdisclosure may be prepared by combining at least one dithiol of Formula(5) and at least one bis(alkenyl) ether of Formula (3) followed byaddition of an appropriate catalyst, and carrying out the reaction at atemperature, for example, within a range from 30° C. to 120° C., such as70° C. to 90° C., for a duration, for example, within a range from 2hours to 24 hours, such as from 2 hours to 6 hours.

Thiol-terminated polythioether prepolymers may comprise a polyfunctionalpolythioether prepolymer, i.e., may have an average thiol functionalitygreater than 2.0. Suitable polyfunctional thiol-terminated polythioetherprepolymers include, for example, those having the structure of Formula(2b):

{HS—R¹—[S—(CH₂)₂—O—(R²—O)_(m)—(CH₂)₂—S—R¹-]_(n)S-V′-}_(z)B  (2b)

wherein z has an average value of greater than 2.0, such as a valuewithin a range from 2.1 and 3, a value within a range from 2.1 and 4, avalue within a range from 3 and 6, or can be an integer from 3 to 6.

Polyfunctionalizing agents suitable for use in preparing suchpolyfunctional thiol-terminated polythioether prepolymers includetri-functionalizing agents, that is, compounds where z is 3. Suitabletri-functionalizing agents include, for example, triallyl cyanurate(TAC), 1,2,3-propanetrithiol, isocyanurate-containing trithiols, andcombinations thereof, as disclosed in U.S. Application Publication No.2010/0010133, which is incorporated by reference in its entirety; andisocyanurates as disclosed, for example, in U.S. Pat. No. 7,858,703,which is incorporated by reference in its entirety. Other usefulpolyfunctionalizing agents include trimethylolpropane trivinyl ether,and the polythiols described in U.S. Pat. Nos. 4,366,307; 4,609,762; and5,225,472, each of which is incorporated by reference in its entirety.Mixtures of polyfunctionalizing agents may also be used. As a result,polythioether prepolymers provided by the present disclosure may have awide range of average functionality. For example, tri-functionalizingagents may afford average functionalities of groups capable of reactingwith thiol groups from 2.05 to 3.0, such as from 2.1 to 2.6. Widerranges of average functionality may be achieved by using tetrafunctionalor higher functionality polyfunctionalizing agents. Functionality mayalso be determined by factors such as stoichiometry, as will beunderstood by those skilled in the art.

Thiol-terminated polythioether prepolymers provided by the presentdisclosure are liquid at room temperature (20° C.-25° C.) and can have aglass transition temperature T_(g), for example, less than −20° C., lessthan −30° C., or less than −40° C. The glass transition temperatureT_(g) is determined by Dynamic Mass Analysis (DMA) using a TAInstruments Q800 apparatus with a frequency of 1 Hz, an amplitude of 20microns, and a temperature ramp of −80° C. to 25° C., with the T_(g)identified as the peak of the tan δ curve.

Thiol-terminated polythioether prepolymers can exhibit a viscosity, forexample, within a range from 20 poise to 500 poise (2 Pa-sec to 50Pa-sec), from 20 poise to 200 poise (2 Pa-sec to 20 Pa-sec) or from 40poise to 120 poise (4 Pa-sec to 12 Pa-sec), measured using a BrookfieldCAP 2000 viscometer, with a No. 6 spindle, at speed of 300 rpm, and atemperature of 25° C.

Thiol-terminated polythioether prepolymers provided by the presentdisclosure can be characterized by a number average molecular weightand/or a molecular weight distribution. Polythioether prepolymers canexhibit a number average molecular weight, for example, from 500 Daltonsto 20,000 Daltons, from 2,000 Daltons to 5,000 Daltons, or from 1,000Daltons to 4,000 Daltons, where the number average molecular weight isdetermined by iodine titration. Thiol-terminated polythioetherprepolymers can exhibit a polydispersity (M_(w)/M_(n); weight averagemolecular weight/number average molecular weight; determined usingiodine titration), for example, from 1 to 20, or from 1 to 5.

The backbone of a thiol-terminated polythioether prepolymer provided bythe present disclosure can be modified to improve the properties such asadhesion, tensile strength, elongation, UV resistance, hardness, and/orflexibility of sealants and coatings prepared using polythioetherprepolymers. For example, adhesion promoting groups, antioxidants, metalligands, and/or urethane linkages can be incorporated into the backboneof a polythioether prepolymer to improve one or more performanceattributes. Examples of backbone-modified polythioether prepolymers aredisclosed, for example, in U.S. Pat. No. 8,138,273 (urethanecontaining), U.S. Pat. No. 9,540,540 (sulfone-containing), U.S. Pat. No.8,952,124 (bis(sulfonyl)alkanol-containing), U.S. Pat. No. 9,382,642(metal-ligand containing), and U.S. Application Publication No.2017/0114208 (antioxidant-containing), PCT Application Publication No.WO 2018/085650 (sulfur-containing divinyl ether), and PCT ApplicationPublication No. WO 2018/031532 (urethane-containing), each of which isincorporated by reference in its entirety.

Permapol® P3.1E, Permapol® P3.1E-2.8, and Permapol® L56086 arethiol-terminated polythioether prepolymers encompassed by the moiety ofFormula (2) and the moiety of Formula (2c) and the thiol-terminatedpolythioether prepolymers of Formula (2a), (2b) and Formula (2d).

Sulfur-containing polythioether prepolymers prepared by the presentdisclosure can also be prepared using sulfur-containing poly(alkenyl)ethers and/or can contain polyurethane and/or polyurea segments in theprepolymer backbone. Sulfur-containing poly(alkenyl) ethers andsulfur-containing polythioether prepolymers prepared usingsulfur-containing poly(alkenyl) ethers are disclosed in PCTInternational Application No. WO 2018/085650, which is incorporated byreference in its entirety. Urethane/urea-containing bis(alkenyl) ethersand sulfur-containing polythioether prepolymers containingurethane/urea-containing bis(alkenyl) ethers are disclosed in U.S.Application Publication No. 2017/0368737, which is incorporated byreference in its entirety.

Polythioether prepolymers provided by the present disclosure cancomprise a backbone of Formula (2c):

—S—R¹—[—S-A-S—R¹—]_(s)—S—  (2c)

-   -   wherein,        -   s is an integer from 1 to 60;        -   each R¹ comprises C₂₋₁₀ alkanediyl, C₆₋₈ cycloalkanediyl,            C₆₋₁₀ alkanecycloalkanediyl, or            —[(—CHR—)_(p)—X—]_(q)—(CHR)_(r)—, wherein each R is            independently selected from hydrogen and methyl, wherein,        -   each X is independently selected from —O— and —S—            -   each p is independently an integer from 2 to 6;            -   q is an integer from 1 to 5; and            -   r is an integer from 2 to 10;        -   each A comprises a moiety of Formula (7), a moiety of            Formula (3a), or a combination thereof:

—(CH₂)₂—O—(CH₂)—Y′—R⁴—Y′—(CH₂)_(n)—O—(CH₂)—  (7)

—(CH₂)₂—O—(R²—O)_(m)—(CH₂)₂—  (3a)

-   -   -   wherein,            -   each n is independently an integer from 1 to 4;            -   each Y′ is independently selected from —O— and —S—; and            -   m is an integer from 0 to 50; and            -   each R² comprises C₂₋₆ n-alkanediyl, C₃₋₆ branched                alkanediyl, C₆₋₈ cycloalkanediyl, C₆₋₁₀                alkanecycloalkanediyl, or                —[(—CH₂—)_(p)—O—]_(q)—(—CH₂—)_(r)—, wherein,                -   each p is independently an integer ranging from 2 to                    6;                -   q is an integer from 1 to 5; and                -   r is an integer from 2 to 10;            -   R⁴ comprises C₂₋₆ n-alkanediyl, C₃₋₆ branched                alkanediyl, C₆₋₈ cycloalkanediyl, C₆₋₁₀                alkanecycloalkanediyl, or                —[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)—, wherein,                -   each X is independently selected from —O—, —S— and                    —S—S—;                -   each p is an integer from 2 to 6;                -   q is an integer from 1 to 5; and                -   r is an integer from 2 to 6; and            -   at least one Y′ is —S—, or R⁴ comprises                —[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)— and at least one X is                —S— or —S—S—; and            -   at least one A comprises a moiety of Formula (7).

In moieties of Formula (2c), s can be an integer, for example, from 1 to40, from 1 to 30, from 1 to 20, or from 1 to 10.

In moieties of Formula (2c), R¹ can be C₂₋₆ n-alkanediyl, such asethane-diyl, n-propane-diyl, n-butane-diyl, n-pentane-diyl, orn-hexane-diyl.

In moieties of Formula (2c), R¹ can be—[(—CHR—)_(p)—X—]_(q)—(—CHR—)_(r)—.

In moieties of Formula (2c), R¹ can be—[(—CHR—)_(p)—X—]_(q)—(—CHR—)_(r)—, where at least one R can be —CH₃.

In moieties of Formula (2c), R¹ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—.

In moieties of Formula (2c), R¹ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, and each X can be —O—.

In moieties of Formula (2c), R¹ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, and each X can be —S— at least one Xcan be —S—, each X can be —S—S—, or at least one X can be —S—S—.

In moieties of Formula (2c), R¹ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, and each p can be 2 and r can be 2.

In moieties of Formula (2c), R¹ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where p can be 1, 2, 3, 4, or 5.

In moieties of Formula (2c), R¹ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where q can be 1, 2, 3, 4, or 5.

In moieties of Formula (2c), R¹ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where r can be 1, 2, 3, 4, or 5.

In moieties of Formula (2c), R¹ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each p can be 2 and r can be2; and q can be 1, 2, 3, 4, or 5.

In moieties of Formula (2c), R¹ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —S— or at leastone X can be —S—; each p can be 2 and r can be 2; and q can be 1, 2, 3,4, or 5.

In moieties of Formula (2c), R¹ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —O— or at leastone X can be —O—; each p can be 2 and r can be 2; and q can be 1, 2, 3,4, or 5.

In moieties of Formula (2c), R¹ can be —[(—CH₂—)_(p)—X—]_(q)—(CH₂)_(r)—,where p is 2, r is 2, q is 1, and X is —S—; R¹ can be—[(—CH₂—)_(p)—X—]_(q)—(CH₂)_(r)—, where p is 2, q is 2, r is 2, and X is—O—; or R¹ can be —[(—CH₂—)_(p)—X—]_(q)—(CH₂)_(r)—, where p is 2, r is2, q is 1, and X is —O—.

In moieties of Formula (7), each n can be 1, 2, 3, or 4.

In moieties of Formula (7), each Y′ can be —O— or each Y′ can be —S—.

In moieties of Formula (7), R⁴ can be C₂₋₆ n-alkanediyl, such asethane-diyl, n-propane-diyl, n-butane-diyl, n-pentane-diyl, orn-hexane-diyl.

In moieties of Formula (7), R⁴ can be C₂₋₆ n-alkanediyl; both Y′ can be—S— or one Y′ can be —S— and the other Y′ can be —O—.

In moieties of Formula (7), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—.

In moieties of Formula (7), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —O— or each Xcan be —S—S— or at least one X can be —O— or at least one X can be—S—S—.

In moieties of Formula (7), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —S— or at leastone X can be —S—.

In moieties of Formula (7), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each p can be 2 and r can be2.

In moieties of Formula (7), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where q can be 1, 2, 3, 4, or 5.

In moieties of Formula (7), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each p can be 2 and r can be2; and q can be 1, 2, 3, 4, or 5.

In moieties of Formula (7), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —S—; each p canbe 2 and r can be 2; and q can be 1, 2, 3, 4, or 5.

In moieties of Formula (7), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —O—; each p canbe 2 and r can be 2; and q can be 1, 2, 3, 4, or 5.

In moieties of Formula (7), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —O—; and each Y′can be —S—.

In moieties of Formula (7), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —S—; and each Y′can be —O—.

In moieties of Formula (7), each n can be 2, each Y— can beindependently selected from —O— and —S—, and R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X is independentlyselected from —O—, —S—, and —S—S—, p is 2, q is selected from 1 and 2,and r is 2.

In moieties of Formula (7), each n can be 2, each Y— can beindependently selected from —O— and —S—, and R⁴ can be C₂₋₄ alkanediyl,such as ethanediyl, n-propanediyl, or n-butanediyl.

In moieties of Formula (3a), m can be an integer, for example, from 1 to20, from 2 to 20, from 2 to 10, from 2 to 6 or from 2 to 4. In moietiesof Formula (3a), m can be, for example, 1, 2, 3, 4, 5, or 6.

In moieties of Formula (3a), each R² can be independently C₂₋₆ nalkanediyl such as 1,2-ethane-diyl, 1,3-propane-diyl, 1,4-butane-diyl,1,5-pentane-diyl or 1,6-hexane-diyl. In moieties of Formula (3a), eachR² can be C₂₋₆ n alkanediyl such as 1,2-ethane-diyl, 1,3-propane-diyl,1,4-butane-diyl, 1,5-pentane-diyl or 1,6-hexane-diyl.

In moieties of Formula (3a), m can be 1, 2, 3, or 4; and R² can be C₂₋₆n alkanediyl such as 1,2-ethane-diyl, 1,3-propane-diyl, 1,4-butane-diyl,1,5-pentane-diyl or 1,6-hexane-diyl

A moiety of Formula (7) can be derived from a sulfur-containingbis(alkenyl) ether, such as a sulfur-containing bis(alkenyl) ether ofFormula (7a):

CH₂═CH—O—(CH₂)_(n)—Y′—R⁴—Y′—(CH₂)_(n)—O—CH═CH₂  (7a)

where n, Y′, and R⁴ are defined as in Formula (2a).

A moiety of Formula (3a) can be derived from a divinyl ether, such as adivinyl ether of Formula (3):

CH₂═CH—O—(—R²—O—)_(m)—CH═CH₂  (3)

where m and R² are defined as in Formula (7)

In polythioether prepolymers comprising a backbone of Formula (2c), eachA can be a moiety of Formula (3a).

In polythioether prepolymers comprising a backbone of Formula (2c), eachA can independently be a moiety of Formula (7a) or a moiety of Formula(3a), where at least one A is a moiety of Formula (7a).

In polythioether prepolymers comprising a backbone of Formula (2c), from20 mol % to 80 mol %, from 30 mol % to 70 mol %, or from 40 mol % to 60mol % of the A moieties can comprise moieties of Formula (3a) and theremaining A moieties can be moieties of Formula (7). For example, in apolythioether prepolymer of Formula (2c), 50 mol % of the A moieties cancomprise a moiety of Formula (3a) and 50 mol % of the A moieties cancomprise a moiety of Formula (7).

In polythioether prepolymers comprising a backbone of Formula (2c), scan be, for example, an integer from 1 to 40, from 1 to 20, from 2 to60, from 2 to 40, from 2 to 20, from 5 to 60, from 5 to 40, from 5 to20, from 10 to 40, or an integer from 10 to 30. Polythioetherprepolymers having a backbone of Formula (2c) can also comprise acombination of polythioether prepolymers having an average value of sfrom 1 to 40, from 1 to 20, from 2 to 60, from 2 to 40, from 2 to 20,from 5 to 60, from 5 to 40, from 5 to 20, from 10 to 40, or from 10 to30, including non-integer values.

Polythioether prepolymers provided by the present disclosure cancomprise urethane/urea-containing bis(alkenyl) ethers incorporated intothe prepolymer backbone. Urethane/urea-containing bis(alkenyl) ethersand polythioether prepolymers containing urethane/urea segments in theprepolymer backbone are disclosed in U.S. Application Publication No.2017/0368737, which is incorporated by reference in its entirety.

Polythioether prepolymers provided by the present disclosure can beprepared, for example, by reacting a polythiol or combination ofpolythiols with a urethane/urea-containing bis(alkenyl) ether orcombination of urethane/urea-containing bis(alkenyl) ethers.

Polythioether prepolymers provided by the present disclosure can beprepared by reacting a polythiol or combination of polythiols, aurethane/urea-containing bis(alkenyl) ether or combination ofurethane/urea-containing bis(alkenyl) ethers, and a divinyl ether orcombination of divinyl ethers.

Polythioether prepolymers provided by the present disclosure cancomprise a backbone of Formula (2c):

—S—R¹—[—S-A-S—R¹—]_(s)—S—  (2c)

-   -   wherein,        -   s is an integer from 1 to 60;        -   each R¹ is selected from C₂₋₁₀ alkanediyl, C₆₋₈            cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl, and            —[(—CHR—)_(p)—X—]_(q)—(CHR)_(r)—, wherein each R is            independently selected from hydrogen and methyl, wherein,            -   each X is independently selected from —O— and —S—            -   each p is independently an integer from 2 to 6;            -   q is an integer from 1 to 5; and            -   r is an integer from 2 to 10;        -   each A independently comprises a moiety of Formula (8) or a            moiety of Formula (3a):

—(CH₂)₂—O—R⁵—Y′—C(═O)—NH—R⁴—NH—C(═O)—Y′—R⁵—O—(CH₂)₂—  (8)

—(CH₂)₂—O—(R²—O)_(m)—(CH₂)₂—  (3a)

-   -   -   wherein,            -   m is an integer from 0 to 50;            -   each Y′ is independently selected from —NH— and —O—; and            -   each R² is independently selected from C₂₋₆                n-alkanediyl, C₃₋₆ branched alkanediyl, C₆₋₈                cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl, and                —[(—CH₂—)_(p)—O—]_(q)—(—CH₂—)_(r)—, wherein,                -   each p is independently an integer ranging from 2 to                    6;                -   q is an integer from 1 to 5; and                -   r is an integer from 2 to 10;            -   R⁴ comprises a core of a diisocyanate;            -   each R⁵ is independently selected from C₁₋₁₀ alkanediyl;                and            -   at least one A comprises a moiety of Formula (8).

In moieties of Formula (2c), each R¹ can be—[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—.

In moieties of Formula (2c), X can be selected from —O— and —S—, andthus —[—(CHR)_(p)—X—]_(q)—(CHR)_(r)— can be—[(—CHR—)_(p)—O—]_(q)—(CHR)_(r)—, —[(—CHR)₂—)_(p)—S—]_(q)—(CHR)_(r)—,—[(—CH₂—)₂—O—]_(q)—(CH₂)₂—, or —[(—CH₂)₂—S—]_(q)—(CH₂)₂—. P and r can beequal, such as both p and r can be 2, 3, or 4.

In moieties of Formula (2c), each R¹ can be selected from C₂₋₆alkanediyl and —[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—.

In moieties of Formula (2c), each R¹ can be—[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—, and X can be —O—, or X can be —S—.

In moieties of Formula (2c), each R¹ can be—[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—, p can be 2, r can be 2, q can be 1, andX can be —S—; or p can be 2, q can be 2, r can be 2, and X can be —O—;or p can be 2, r can be 2, q can be 1, and X can be —O—.

In moieties of Formula (2c), each R¹ can be—[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—, each R can be hydrogen, or at least oneR can be methyl.

In moieties of Formula (2c), each R¹ can be derived fromdimercaptodioxaoctane (DMDO) or each R¹ is derived fromdimercaptodiethylsulfide (DMDS).

In moieties of Formula (2c), each R¹ can be —[(CH₂)₂—O—]₂—(CH₂)₂—.

In moieties of Formula (2c), each R¹ can be—[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—, each p can independently be selectedfrom 2, 3, 4, 5, and 6; or each p can be the same and can be 2, 3, 4, 5,or 6.

In moieties of Formula (2c), each R¹ can be—[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—, each r can be selected from 2, 3, 4, 5,6, 7, and 8.

In moieties of Formula (2c), each R¹ can be—[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—, each q can be selected from 1, 2, 3, 4,and 5.

In moieties of Formula (2c), each R¹ can be—[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—, each m can independently be an integerfrom 1 to 3. Each m can be the same such as 0, 1, 2, or 3.

In polythioether prepolymers of Formula (2c), s can be an integer from 0to 30, an integer from 0 to 20, an integer from 0 to 10, or an integerfrom 0 to 5.

In polythioether prepolymers of Formula (2c), s can be 0, 1, 2, 3, 4, 5,6, 7, 8, 9, or 10.

In polythioether prepolymers of Formula (2c), R¹ is—[(—CH₂—)_(p)—X—]_(q)—(CH₂)_(r)—, where p is 2, X is —O—, q is 2, r is2, R² is ethanediyl, m is 2, and n is 9.

In polythioether prepolymers of Formula (2c), R¹ is selected from C₂₋₆alkanediyl and —[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—.

In moieties of Formula (2c), R¹ is —[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—, andX is —O— or X is —S—.

In moieties of Formula (2c), where R¹ is—[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—, p is 2, r is 2, q is 1, and X is —S—;or where p is 2, q is 2, r is 2, and X is —O—; or p is 2, r is 2, q is1, and X is —O—.

In moieties of Formula (2c), where R¹ is—[—(CHR)_(p)—X—]_(q)—(CHR)_(r)—, each R is hydrogen, or at least one Ris methyl.

In moieties of Formula (2c), each R¹ is the same, or at least one R¹ isdifferent.

In moieties of Formula (2c), s can be an integer from 1 to 20, or aninteger from 1 to 10, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

In moieties of Formula (2c), each R¹ can be C₂₋₄ alkanediyl,n-ethane-diyl, n-propane-diyl, n-butane-diyl, n-pentane-diyl, orn-hexane-diyl.

A moiety of Formula (2c) can be derived from a urethane/urea-containingbis(alkenyl) ether, such as a urethane/urea-containing bis(alkenyl)ether of Formula (8a):

CH₂═CH—O—R⁵—Y′—C(═O)—NH—R⁴—NH—C(═O)—Y′—R—O—CH═CH₂  (8a)

where Y′, R⁴, and R⁵ are defined as in Formula (8).

A moiety of Formula (3a) can be derived from a divinyl ether, such as adivinyl ether of Formula (3):

CH₂═CH—O—(—R²—O—)_(m)—CH═CH₂  (3)

where m and R² are defined as in Formula (3a).

In polythioether prepolymers comprising a backbone of Formula (2c), eachA can be a moiety of Formula (8).

In polythioether prepolymers comprising a backbone of Formula (2c), eachA can independently be a moiety of Formula (8) or a moiety of Formula(3a), where at least one A is a moiety of Formula (8).

In polythioether prepolymers comprising a backbone of Formula (2c), from1 mol % to 20 mol %, from 1 mol % to 15 mol %, from 1 mol % to 10 mol %,or from 2 mol % to 8 mol % of the A moieties can comprise moieties ofFormula (8) and the remaining A moieties can be moieties of Formula(3a), where mol % is based on the total moles of -A- in the backbone ofFormula (2c). For example, in a polythioether prepolymer of Formula(2c), 5 mol % of the A moieties can comprise a moiety of Formula (8) and95 mol % of the A moieties can comprise a moiety of Formula (3a), wheremol % is based on the total moles of moieties of Formula (8) andmoieties of Formula (3a) forming the polythioether prepolymer comprisinga backbone of Formula (2c).

In polythioether prepolymers comprising a backbone of Formula (2c), mcan be, for example, an integer from 1 to 40, from 1 to 20, from 2 to60, from 2 to 40, from 2 to 20, from 5 to 60, from 5 to 40, from 5 to20, from 10 to 40, or an integer from 10 to 30.

In polythioether prepolymers of Formula (2c) the polythioetherprepolymer can comprise a thiol-terminated polythioether prepolymer ofFormula (2d), a thiol-terminated polythioether prepolymer of Formula(2e), or a combination thereof:

HS—R¹—[—S-A-S—R¹—]_(s)—SH  (2d)

{HS—R¹—[—S-A-S—R¹—]_(s)—S-V′-}_(z)B  (2e)

where s, R¹, A, B, z, and V′ are defined as for Formula (2c) and Formula(8); and at least one A comprises a moiety of Formula (3a).

A thiol-terminated sulfur-containing prepolymer can comprise athiol-terminated sulfur-containing polyformal.

Sulfur-containing polyformal prepolymers useful in sealant applicationsare disclosed, for example, in U.S. Pat. No. 8,729,216 and in U.S. Pat.No. 8,541,513, each of which is incorporated by reference in itsentirety.

A thiol-terminated sulfur-containing polyformal prepolymer can have thestructure of Formula (9):

R³—R¹—(S)_(p)—R¹—[O—C(R²)₂—O—R¹—(S)_(p)—R¹—]_(n)—R³  (9)

where n is an integer selected from 1 to 50; each p is independentlyselected from 1 and 2; each R¹ comprises C₂₋₆ alkanediyl; each R²independently comprises hydrogen, C₁₋₆ alkyl, C₇₋₁₂ phenylalkyl,substituted C₇₋₁₂ phenylalkyl, C₆₋₁₂ cycloalkylalkyl, substituted C₆₋₁₂cycloalkylalkyl, C₃₋₁₂ cycloalkyl, substituted C₃₋₁₂ cycloalkyl, C₆₋₁₂aryl, and substituted C₆₋₁₂ aryl; and each R³ is —OR^(3′) wherein R^(3′)comprises a thiol-terminated group.

In sulfur-containing polyformal prepolymers of Formula (9), each R¹ canindependently be C₂₋₆ alkanediyl, C₂₋₄ alkanediyl, C₂₋₃ alkanediyl, orethane-1,2-diyl. In sulfur-containing polyformal prepolymers of Formula(9), each R¹ can be ethane-1,2-diyl.

In sulfur-containing polyformal prepolymers of Formula (9), each R² canindependently be hydrogen, C₁₋₆ alkyl, C₁₋₄ alkyl, C₁₋₃ alkyl, or C₁₋₂alkyl. In sulfur-containing polyformal prepolymers of Formula (9), eachR² can be hydrogen, methyl, or ethyl.

In sulfur-containing polyformal prepolymers of Formula (9), each R¹ canbe the same and can be C₂₋₃ alkanediyl such as ethane-1,2-diyl orpropane-1,3-diyl; and each R² can be the same and can be hydrogen orC₁₋₃ alkyl such as methyl, ethyl, or propyl. In sulfur-containingpolyformal prepolymers of Formula (9), each R¹ can be ethane-1,2-diyl.In sulfur-containing polyformal prepolymers of Formula (9), each R² canbe hydrogen. In sulfur-containing polyformal prepolymers of Formula (9),each R¹ can be ethane-1,2-diyl and each R² can be hydrogen.

In sulfur-containing polyformal prepolymers of Formula (9), n can be aninteger selected from 1 to 50, an integer from 2 to 40, an integer from4 to 30, or n can be an integer from 7 to 30.

In sulfur-containing polyformal prepolymers of Formula (9), each p isthe same and can be 1, and each p is the same and can be 2.

In sulfur-containing polyformal prepolymers of Formula (9) can have anumber average molecular weight from 200 Daltons to 6,000 Daltons, from500 Daltons to 5,000 Daltons, from 1,000 Daltons to 5,000 Daltons, from1,500 Daltons to 4000 Daltons, or from 2,000 Daltons to 3,600 Daltons,where the number average molecular weight is determined by gelpermeation chromatography using a polystyrene standard.

In sulfur-containing polyformal prepolymers of Formula (9), each R³ canbe a thiol-terminated group and can comprise a group of Formula (a),Formula (b), Formula (c), Formula (d), Formula (e), Formula (f), Formula(g), or Formula (h):

HS—R⁷—R⁶—O—  (a)

HS—R⁷—O—  (b)

HS—R⁷—S—  (c)

HS—  (d)

HS—R⁷—NH—C(═O)—O—  (e)

HS—R⁷—C(═O)—O—R⁹—NH—C(═O)—O—  (f)

HS—R⁷—C(═O)—NH—R⁹—NH—C(═O)—O—  (g)

HS—R⁷—C(═O)—O—  (h)

where each R⁶ can be a moiety derived from a diisocyanate or a moietyderived from an ethylenically unsaturated monoisocyanate; each R⁷ can beC₂₋₁₄ alkanediyl or C₂₋₁₄ heteroalkanediyl; and each R⁹ can be C₂₋₆alkanediyl, C₂₋₆ heteroalkanediyl, C₆₋₁₂ arenediyl, substituted C₆₋₁₂arenediyl, C₆₋₁₂ heteroarenediyl, substituted C₆₋₁₂ heteroarenediyl,C₃₋₁₂ cycloalkanediyl, substituted C₃₋₁₂ cycloalkanediyl, C₃₋₁₂heterocycloalkanediyl, substituted C₃₋₁₂ heterocycloalkanediyl, C₇₋₁₈alkanearenediyl, substituted C₇₋₁₈ heteroalkanearenediyl, C₄₋₁₈alkanecycloalkanediyl, or substituted C₄₋₁₈ alkanecycloalkanediyl.

Sulfur-containing polyformal prepolymers provided by the presentdisclosure can have the structure of Formula (10):

{R⁶—R¹—(S)_(p)—R¹—[O—C(R³)₂—O—R¹—(S)_(p)—R¹—]_(n)—O—C(R³)₂—O—}_(m)—Z  (10)

where each n is an integer selected from 1 to 50; m is an integerselected from 3 to 6; p is independently comprises 1 or 2; each R¹independently comprises C₂₋₆ alkanediyl; each R³ independently compriseshydrogen, C₁₋₆ alkyl, C₇₋₁₂ phenylalkyl, substituted C₇₋₁₂ phenylalkyl,C₆₋₁₂ cycloalkylalkyl, substituted C₆₋₁₂ cycloalkylalkyl, C₃₋₁₂cycloalkyl, substituted C₃₋₁₂ cycloalkyl, C₆₋₁₂ aryl, or substitutedC₆₋₁₂ aryl; each R⁵ is —OR^(5′) wherein R^(5′) can be a thiol-terminatedgroup; and Z represents the core of an m-valent parent polyol Z(OH)_(m).

In sulfur-containing polyformal prepolymers of Formula (10), each R¹ canindependently be C₂₋₆ alkanediyl, C₂₋₄ alkanediyl, C₂₋₃ alkanediyl, orethane-1,2-diyl. In sulfur-containing polyformal prepolymers of Formula(10), each R¹ can be ethane-1,2-diyl.

In sulfur-containing polyformal prepolymers of Formula (10), each R³ canindependently be hydrogen, C₁₋₆ alkyl, C₁₋₄ alkyl, C₁₋₃ alkyl, or C₁₋₂alkyl. In sulfur-containing polyformal prepolymers of Formula (10), eachR³ can be hydrogen, methyl, or ethyl.

In sulfur-containing polyformal prepolymers of Formula (10), each R¹ canbe the same and can be C₂₋₃ alkanediyl such as ethane-1,2-diyl orpropane-1,3-diyl; and each R³ is the same and can be hydrogen or C₁₋₃alkyl such as methyl, ethyl, or propyl. In sulfur-containing polyformalprepolymers of Formula (10), each R¹ can be ethane-1,2-diyl. Insulfur-containing polyformal prepolymers of Formula (10), each R³ can behydrogen. In sulfur-containing polyformal prepolymers of Formula (10),each R¹ can be ethane-1,2-diyl and each R³ can be hydrogen.

In sulfur-containing polyformal prepolymers of Formula (10), m can be 1,m can be 2, m can be 3, m can be 4, m can be 5, or m can be 6.

In sulfur-containing polyformal prepolymers of Formula (10) where m is3, the parent polyol Z(OH)_(m) can be a triol of Formula (11):

where each R² is independently C₁₋₆ alkanediyl, or a triol of Formula(12):

where each R² is independently C₁₋₆ alkanediyl. Accordingly, in theseembodiments Z can have the structure:

respectively, where each R² is independently C₁₋₆ alkanediyl.

In sulfur-containing polyformal prepolymers of Formula (10), each n canbe an integer selected from 1 to 50, an integer selected from 2 to 40,an integer selected from 4 to 30, or an integer selected from 7 to 30.

In sulfur-containing polyformal prepolymers of Formula (10), each p canbe the same and is 1, and each p is the same and is 2.

In sulfur-containing polyformal prepolymers of Formula (10) has a numberaverage molecular weight from 200 Daltons to 6,000 Daltons, from 500Daltons to 5,000 Daltons, from 1,000 Daltons to 5,000 Daltons, from1,500 Daltons to 4000 Daltons, or from 2,000 Daltons to 3,600 Daltons,where the weight average molecular weight is determined by gelpermeation chromatography using a polystyrene standard.

In sulfur-containing polyformal prepolymers of Formula (10), R⁶ is—OR^(5′), wherein each R⁵ can be the same.

In sulfur-containing polyformal prepolymers of Formula (10), each R⁵ canbe a thiol-terminated group of Formula (a), Formula (b), Formula (c),Formula (d), Formula (e), Formula (f), Formula (g), or Formula (h):

HS—R⁷—R⁶—O—  (a)

HS—R⁷—O—  (b)

HS—R⁷—S—  (c)

HS—  (d)

HS—R⁷—NH—C(═O)—O—  (e)

HS—R⁷—C(═O)—O—R⁹—NH—C(═O)—O—  (f)

HS—R⁷—C(═O)—NH—R⁹—NH—C(═O)—O—  (g)

HS—R⁷—C(═O)—O—  (h)

where each R⁶ can be a moiety derived from a diisocyanate or a moietyderived from an ethylenically unsaturated monoisocyanate; each R⁷ can beC₂₋₁₄ alkanediyl or C₂₋₁₄ heteroalkanediyl; and each R⁹ can be C₂₋₆alkanediyl, C₂₋₆ heteroalkanediyl, C₆₋₁₂ arenediyl, substituted C₆₋₁₂arenediyl, C₆₋₁₂ heteroarenediyl, substituted C₆₋₁₂ heteroarenediyl,C₃₋₁₂ cycloalkanediyl, substituted C₃₋₁₂ cycloalkanediyl, C₃₋₁₂heterocycloalkanediyl, substituted C₃₋₁₂ heterocycloalkanediyl, C₇₋₁₈alkanearenediyl, substituted C₇₋₁₈ heteroalkanearenediyl, C₄₋₁₈alkanecycloalkanediyl, or substituted C₄₋₁₈ alkanecycloalkanediyl.

A thiol-terminated sulfur-containing prepolymer can comprise athiol-terminated polysulfide prepolymer.

A polysulfide prepolymer refers to a prepolymer that contains one ormore polysulfide linkages, i.e., —S_(x)— linkages, where x is from 2 to4, in the prepolymer backbone and/or in pendant positions on theprepolymer chain. A polysulfide prepolymer can have two or moresulfur-sulfur linkages. Suitable polysulfides are commerciallyavailable, for example, from AkzoNobel and Toray Industries, Inc. underthe names Thioplast® and Thiokol-LP®, respectively.

Examples of suitable polysulfide prepolymers are disclosed, for example,in U.S. Pat. Nos. 4,623,711; 6,172,179; 6,509,418; 7,009,032; and7,879,955, each of which is incorporated by reference in its entirety.

Examples of suitable thiol-terminated polysulfides include Thioplast™ Gpolysulfides such as Thioplast™ G1, Thioplast™ G4, Thioplast™ G10,Thioplast™ G12, Thioplast™ G21, Thioplast™ G22, Thioplast™ G44,Thioplast™ G122, and Thioplast™ G131, which are commercially availablefrom AkzoNobel. Thioplast™ G resins are liquid polysulfide polymers thatare blends of di- and tri-functional molecules where the difunctionalpolysulfide polymers have the structure of Formula (13):

SH—(—R—S—S—)_(n)—R—SH  (13)

and the trifunctional polysulfide polymers have the structure of Formula(14):

HS—(—R—S—S—)_(a)—CH₂—CH{—CH₂—(—S—S—R—)_(b)—SH}{—(—S—S—R—)_(c)—SH}  (14)

where each R is —(CH₂)₂—O—CH₂—O—(CH₂)₂—, and n=a+b+c, where the valuefor n may be from 7 to 38 depending on the amount of the trifunctionalcross-linking agent (1,2,3,-trichloropropane; TCP) used during synthesisof the polysulfide polymer. Thioplast™ G polysulfides can have amolecular weight from less than 1,000 Daltons to 6,500 Daltons, a SHcontent from 1% to greater than 5.5%, and a cross-linking density from0% to 2.0%.

Examples of suitable thiol-terminated polysulfide prepolymers alsoinclude Thiokol™ LP polysulfides available from Toray Industries, Inc.such as Thiokol™ LP2, Thiokol™ LP3, Thiokol™ LP12, Thiokol™ LP23,Thiokol™ LP33, and Thiokol™ LP55. Thiokol™ LP polysulfides have anaverage molecular weight from 1,000 Daltons to 7,500 Daltons, a SHcontent from 0.8% to 7.7%, and a cross-linking density from 0% to 2%.

A thiol-terminated sulfur-containing prepolymer can comprise aThiokol-LP® polysulfide, a Thioplast® G polysulfide, or a combinationthereof.

A thiol-terminated sulfur-containing prepolymer can comprise athiol-terminated monosulfide.

A thiol-terminated monosulfide can comprise a thiol-terminatedmonosulfide of Formula (15a), a thiol-terminated monosulfide of Formula(15b), or a combination thereof:

HS—R²—[—S—(R—X)_(p)—(R¹—X)R²—]_(n)—SH  (15a)

{HS—R²—[—S—(R—X)_(p)(R¹—X)_(q)—R²—]_(n)—S-V′-}_(z)B  (15b)

-   -   where,        -   each X independently can be S, O, or NR³, where R³ can be            C¹⁻⁴ alkyl;        -   p is an integer from 1 to 5;        -   q is an integer from 0 to 5;        -   n is an integer from 1 t0 60;        -   each R can independently be C₂₋₁₀ alkanediyl, C₆₋₈            cycloalkanediyl, C₁₋₄ alkylcycloalkanediyl, or C₈₋₁₀            alkylarenediyl;        -   each R¹ can independently be C₁₋₁₀ alkanediyl, C₆₋₈            cycloalkanediyl, C₁₋₄ alkylcycloalkanediyl, or C₈₋₁₀            alkylarenediyl;        -   each R² can independently be C₂₋₁₀ alkanediyl, C₆₋₈            cycloalkanediyl, C₁₋₄ alkylcycloalkanediyl, or C₈₋₁₀            alkylarenediyl;        -   B represents a core of a z-valent polyfunctionalizing agent            B(-V)_(z) wherein:            -   z is an integer from 3 to 6; and            -   each V is a moiety comprising a terminal group reactive                with a thiol group; and        -   each -V′- is derived from the reaction of -V with a thiol.

In thiol-terminated monosulfides of Formula (15a) and (15b), each X canindependently be S or O, each X can be S, or each X can be O.

In thiol-terminated monosulfides of Formula (15a) and (15b), p can be aninteger from 2 to 6, or p can be 1, 2, 3, 4, 5, or 6.

In thiol-terminated monosulfides of Formula (15a) and (15b), q can be aninteger from 1 to 5, q can be an integer from 2 to 5, or q can be 0, 1,2, 3, 4, or 5.

In thiol-terminated monosulfides of Formula (15a) and (15b), n can be aninteger from 2 to 60, from 3 to 60, or from 25 to 35.

In thiol-terminated monosulfides of Formula (15a) and (15b), each R canindependently be C₂₋₁₀ alkanediyl or C₆₋₈ cycloalkanediyl, each R can beC₂₋₁₀ alkanediyl, or each R can be C₆₋₈ cycloalkanediyl.

In thiol-terminated monosulfides of Formula (15a) and (15b), each R canbe C₂₋₆ alkanediyl, C₂₋₄ alkanediyl, C₃₋₁₀ alkanediyl, or C₃₋₆alkanediyl.

In thiol-terminated monosulfides of Formula (15a) and (15b), each R canbe ethanediyl, 1,3-propanediyl, 1,2-propanediyl, 1,4-butanediyl, or1,3-butanediyl.

In thiol-terminated monosulfides of Formula (15a) and (15b), each R¹ canindependently be C₁₋₁₀ alkanediyl or C₆₋₈ cycloalkanediyl, each R cancomprise C₁₋₁₀ alkanediyl, or each R¹ can comprise C₆₋₈ cycloalkanediyl.

In thiol-terminated monosulfides of Formula (15a) and (15b), each R¹ canbe C₁₋₆ alkanediyl, C₁₋₄ alkanediyl, C₂₋₁₀ alkanediyl, or C₂₋₆alkanediyl.

In thiol-terminated monosulfides of Formula (15a) and (15b), each R¹ canbe methanediyl, ethanediyl, 1,3-propanediyl, 1,2-propanediyl,1,4-butanediyl, or 1,3-butanediyl.

In thiol-terminated monosulfides of Formula (15a) and (15b), each R² canindependently be C₂₋₁₀ alkanediyl or C₆₋₈ cycloalkanediyl, each R² cancomprise C₂₋₁₀ alkanediyl, or each R² can be C₆₋₈ cycloalkanediyl.

In thiol-terminated monosulfides of Formula (15a) and (15b), each R² canbe C₂₋₆ alkanediyl, C₂₋₄ alkanediyl, C₃₋₁₀ alkanediyl, or C₃₋₆alkanediyl.

In thiol-terminated monosulfides of Formula (15a) and (15b), each R² canbe ethanediyl, 1,3-propanediyl, 1,2-propanediyl, 1,4-butanediyl, or1,3-butanediyl.

In thiol-terminated monosulfides of Formula (15a) and (15b), p can be 1or 2, q can be 1 or 2, n can be an integer from 1 to 60 or an integerfrom 25 to 35, each X can be O or S, each R can be C₂₋₄ alkanediyl, eachR¹ can be C₁₋₄ alkanediyl, and each R² can be C₂₋₄ alkanediyl.

In thiol-terminated monosulfides of Formula (15a) and (15b), p can be 1or 2, q can be 1 or 2, n can be an integer from 1 to 60 or an integerfrom 25 to 35, each X can be O or S, each R can be C₂ alkanediyl, eachR¹ can be C₁ alkanediyl, and each R² can be C₂ alkanediyl.

In thiol-terminated monosulfides of Formula (15a) and (15b), p can be 1or 2, q can be 1 or 2, n can be an integer from 1 to 60 or an integerfrom 25 to 35, each X can be O, each R can be C₂ alkanediyl, each R¹ canbe C₁₋₄ alkanediyl, and each R² can be C₂ alkanediyl.

In thiol-terminated monosulfides of Formula (15a) and (15b), Brepresents a core of a z-valent polyfunctionalizing agent B(-V)_(z) andB(-V)_(z) can be 1,2,3-trichloropropane,1,1,1-tris(chloromethyl)propane, 1,1,1-tris(chloromethyl)ethane, and1,3,5-tris(chloromethyl)benzene, or a combination of any of theforegoing.

Thiol-terminated monosulfides of Formula (15a) and (15b) can be preparedby reacting an α,ω-dihalo organic compounds, a metal hydrosulfide, ametal hydroxide, and an optional polyfunctionalizing agent. Examples ofsuitable α,ω-dihalo organic compounds include bis(2-chloroethyl)formal.Examples of suitable metal hydrosulfides and metal hydroxides includesodium hydrosulfide and sodium hydroxide. Examples of suitablepolyfunctionalizing agents include 1,2,3-trichloropropane,1,1,1-tris(chloromethyl)propane, 1,1,1-tris(chloromethyl)ethane, and1,3,5-tris(chloromethyl)benzene. Methods of synthesizingthiol-terminated monosulfides of Formula (15a) and (15b) are disclosed,for example, in U.S. Pat. No. 7,875,666, which is incorporated byreference in its entirety.

A thiol-terminated monosulfide can comprise a thiol-terminatedmonosulfide of Formula (16a), a thiol-terminated monosulfide of Formula(16b), or a combination thereof:

H—[—S—(R—X)_(p)—C(R′)₂—(X—R)_(q)—]_(n)—SH  (16a)

{H—[—S—(R—X)_(p)—C(R′)₂—(X—R)_(q)—]_(n)—S-V′-}_(z)B  (16b)

-   -   where,        -   each X can independently be S or O;        -   p is an integer from 1 to 5;        -   q is an integer from 1 to 5;        -   n is an integer from 1 to 60;        -   each R can independently be C₂₋₁₀ alkanediyl;        -   each R¹ can independently be hydrogen or C₁₋₁₀ alkanediyl;        -   B represents a core of a z-valent polyfunctionalizing agent            B(-V)_(z) wherein:            -   z is an integer from 3 to 6; and            -   each V is a moiety comprising a terminal group reactive                with a thiol group; and        -   each -V′- is derived from the reaction of -V with a thiol.

In thiol-terminated monosulfides of Formula (16a) and (16b), each X canbe S, or each X can be O.

In thiol-terminated monosulfides of Formula (16a) and (16b), p can be aninteger from 2 to 5, or q can be 1, 2, 3, 4, or 5.

In thiol-terminated monosulfides of Formula (16a) and (16b), n can be aninteger from 2 to 60, from 3 to 60, or from 25 to 35.

In thiol-terminated monosulfides of Formula (16a) and (16b), each R canindependently be C₂₋₆ alkanediyl or C₂₋₄ alkanediyl.

In thiol-terminated monosulfides of Formula (16a) and (16b), each R canbe ethanediyl, 1,3-propanediyl, 1,2-propanediyl, 1,4-butanediyl, or1,3-butanediyl.

In thiol-terminated monosulfides of Formula (16a) and (16b), each R canbe C₂₋₁₀ n-alkanediyl, C₂₋₁₀ branched alkanediyl, or a combinationthereof.

In thiol-terminated monosulfides of Formula (16a) and (16b), each R¹ canindependently be hydrogen or C₂₋₆ alkanediyl.

In thiol-terminated monosulfides of Formula (16a) and (16b), each R¹ canindependently be hydrogen, ethanediyl, 1,3-propanediyl, 1,2-propanediyl,1,4-butanediyl, or 1,3-butanediyl.

In thiol-terminated monosulfides of Formula (16a) and (16b), each R¹ canbe C₁₋₁₀ n-alkanediyl, C₁₋₁₀ branched alkanediyl, or a combinationthereof.

In thiol-terminated monosulfides of Formula (16a) and (16b), each X isO, p is 1 or 2, q is 1 or 2, n is 1 to 60 such as 2 to 60, each R isC₂₋₄ alkanediyl such as ethanediyl, and each R¹ is hydrogen.

In thiol-terminated monosulfides of Formula (16a) and (16b), each X isO, p is 1, q is 1, n is 1 to 60 such as 2 to 60, each R is C₂₋₄alkanediyl such as ethanediyl, and each R¹ is hydrogen.

In thiol-terminated monosulfides of Formula (16a) and (16b), each X isO, p is 2, q is 2, n is 1 to 60 such as 2 to 60, each R is C₂₋₄alkanediyl such as ethanediyl, and each R¹ is hydrogen.

In thiol-terminated monosulfides of Formula (16a) and (16b), Brepresents a core of a z-valent polyfunctionalizing agent B(-V)_(z) andB(-V)_(z) can be 1,2,3-trichloropropane,1,1,1-tris(chloromethyl)propane, 1,1,1-tris(chloromethyl)ethane, and1,3,5-tris(chloromethyl)benzene, or a combination of any of theforegoing.

Thiol-terminated monosulfides of Formula (16a) and (16b) can be preparedby reacting an α,ω-dihalo organic compounds, a metal hydrosulfide, ametal hydroxide, and an optional polyfunctionalizing agent. Examples ofsuitable α,ω-dihalo organic compounds include bis(2-chloroethyl)formal.Examples of suitable metal hydrosulfides and metal hydroxides includesodium hydrosulfide and sodium hydroxide. Examples of suitablepolyfunctionalizing agents include 1,2,3-trichloropropane,1,1,1-tris(chloromethyl)propane, 1,1,1-tris(chloromethyl)ethane, and1,3,5-tris(chloromethyl)benzene. Methods of synthesizingthiol-terminated monosulfides of Formula (16a) and (16b) are disclosed,for example, in U.S. Pat. No. 8,466,220, which is incorporated byreference in its entirety.

A thiol-terminated monosulfide can comprise a thiol-terminatedmonosulfide of Formula (17a), a thiol-terminated monosulfide of Formula(17b), or a combination thereof:

HS—R—(S_(y)—R)_(t)—SH  (17a)

{HS—R—(S_(y)—R)_(t)—S-V′-}_(z)B  (17b)

-   -   where,        -   t is an integer from 1 to 60;        -   y has an average value within a range from 1.0 to 1.5;        -   each R can independently be branched alkanediyl, branched            arenediyl, or a moiety having the structure            —(CH₂)_(p)—O—(CH₂)_(q)—O—(CH₂)_(r)—; wherein,            -   q is an integer from 1 to 8;            -   p is an integer from 1 to 10; and            -   r is an integer from 1 to 10;        -   B represents a core of a z-valent polyfunctionalizing agent            B(-V)_(z) wherein:            -   z is an integer from 3 to 6; and            -   each V is a moiety comprising a terminal group reactive                with a thiol group; and        -   each -V′- is derived from the reaction of -V with a thiol.

In thiol-terminated monosulfides of Formula (17a) and Formula (17b), tcan be, for example, an integer from 2 to 60, from 1 to 40, or from 1 to20.

In thiol-terminated monosulfides of Formula (17a) and Formula (17b),where R is —(CH₂)_(p)—O—(CH₂)_(q)—O—(CH₂)_(r)—, q can be, for example,an integer from 1 to 6, or an integer from 1 to 4. For example, q can be1, 2, 3, 4, 5 or 6.

In thiol-terminated monosulfides of Formula (17a) and Formula (17b),where R is —(CH₂)_(p)—CH₂)_(q))_(q)—O—(CH₂)_(r)—, each p can be, forexample, an integer from 1 to 6 or from 1 to 4. For example, each p canbe 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

In thiol-terminated monosulfides of Formula (17a) and Formula (17b),where R is —(CH₂)_(p)—O—(CH₂)_(q)—O—(CH₂)_(r)—, each r can be, forexample, an integer from 1 to 6 or from 1 to 4. For example, each p canbe 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

In thiol-terminated monosulfides of Formula (17a) and Formula (17b), ycan have a value of 1.

In thiol-terminated monosulfides of Formula (17a) and Formula (17b), Rcan be —(CH₂)_(p)—O—(CH₂)_(q)—O—(CH₂)_(r)—.

In thiol-terminated monosulfides of Formula (17a) and Formula (17b), Rcan be —(CH₂)_(p)—O—(CH₂)_(q)—O—(CH₂)_(r)—, each q can be 1, 2, 3, or 4,and each p and r can be 1 or 2.

In thiol-terminated monosulfides of Formula (17a) and Formula (17b), 0mol % to 20 mol % of the R groups can comprise branched alkanediyl orbranched arenediyl, and 80 mol % to 100 mol % of the R groups cancomprise —(CH₂)_(p)—O—(CH₂)_(q)—O—(CH₂)_(r)—, where mol % is based onthe total moles of R groups.

In thiol-terminated monosulfides of Formula (17a) and Formula (17b), Brepresents a core of a z-valent polyfunctionalizing agent B(-V)_(z) andB(-V)_(z) can comprise, for example, 1,2,3-trichloropropane,1,1,1-tris(chloromethyl)propane, 1,1,1-tris(chloromethyl)ethane, and1,3,5-tris(chloromethyl)benzene, or a combination of any of theforegoing.

Thiol-terminated monosulfides of Formula (17a) and Formula (17b) can beprepared by reacting an α,ω-dihalo organic compound, a metalhydrosulfide, a metal hydroxide, and an optional polyfunctionalizingagent. Examples of suitable α,ω-dihalo organic compounds includebis(2-chloroethyl)formal. Examples of suitable metal hydrosulfides andmetal hydroxides include sodium hydrosulfide and sodium hydroxide.Examples of suitable polyfunctionalizing agents include1,2,3-trichloropropane, 1,1,1-tris(chloromethyl)propane,1,1,1-tris(chloromethyl)ethane, and 1,3,5-tris(chloromethyl)benzene.

Examples of thiol-terminated monosulfides of Formula (17a) and Formula(17b) are disclosed, for e U.S. Application Publication No. 2016/0152775and in U.S. Pat. No. 9,079,833.

A thiol-terminated monosulfide can comprise a thiol-terminatedmonosulfide of Formula (18):

HS—(R—O—CH₂—O—R—S_(m)—)_(n-1)—R—O—CH₂—O—R—SH  (18)

where R is C₂₋₄ alkanediyl, m is 1-8, and n is an integer from 2 to 370

In thiol-terminated monosulfides of Formula (18), m can be, for example,an integer from 1 to 6, and integer from 1 to 4, or the integer 1, 2, 3,4, 5, 6, 7, or 8.

In thiol-terminated monosulfides of Formula (18), n can be, for example,an integer from 2 to 200 or an integer from 2 to 100.

In thiol-terminated monosulfides of Formula (18), each R canindependently be ethanediyl, 1,3-propanediyl, 1,1-propanediyl,1,2-propanediyl, 1,4-butanediyl, 1,1-butanediyl, 1,2-butanediyl, or1,3-butanediyl.

Examples of thiol-terminated monosulfides of Formula (18) are disclosed,for example, in JP 62-53354.

Thiol-terminated monosulfides can be liquid at room temperature.Thiol-terminated monosulfides can have a viscosity, at 100% solids, ofno more than 1,500 poise (150 Pa-sec), such as 40 poise to 500 poise (4Pa-sec to 50 Pa-sec), at a temperature of about 25° C. and a pressure ofabout 760 mm Hg (101 kPa) determined according to ASTM D-2849 § 79-90using a Brookfield CAP 2000 viscometer.

Thiol-terminated monosulfides can have a number average molecular weightwithin a range from 300 Daltons to 10,000 Daltons, such as within arange 1,000 Daltons to 8,000 Daltons, the molecular weight beingdetermined by gel-permeation chromatography using a polystyrenestandard. Thiol-terminated monosulfides can have a glass transitiontemperature T_(g) less than −40° C., less than −55° C., or less than−60° C.

Thiol-terminated sulfur-containing prepolymers can be modified toinclude terminal alkenyl groups by reacting the thiol-terminatedsulfur-containing prepolymer with a polyalkenyl ether, such as abis(alkenyl)ether under suitable reaction conditions.

Compositions provided by the present disclosure can comprise apolyalkenyl or combination of polyalkenyls. A polyalkenyl can bedifunctional, or can have a alkenyl-functionality greater than two (2)such as from 3 to 6, including an alkenyl functionality of 3, 4, 5, or6. A polyalkenyl can comprise a polyallyl compound, a bis(alkenyl)ether, a sulfur-containing bis(alkenyl) ether, or a combination of anyof the foregoing. A polyalkenyl can react with a thiol-terminatedsulfur-containing prepolymer via a free radical reaction, such as a dualcure free radical reaction mechanism, to provide a cured sealant.

Curable compositions provided by the present disclosure can comprise,for example, from 1 wt % to 10 wt % of a polyalkenyl or combination ofpolyalkenyls, from 2 wt % to 9 wt %, from 3 wt % to 8 wt %, or from 4 wt% to 7 wt % of a polyalkenyl or combination of polyalkenyl, where wt %is based on the total weight of the curable composition.

A polyalkenyl can comprise any suitable compound comprising two or morealkenyl groups. A polyalkenyl can comprise an alkenyl-terminatedprepolymer, such as an alkenyl-terminated sulfur-containing prepolymer.A polyalkenyl can comprise a polyalkenyl monomer, having a low molecularweight such as, for example, a molecular weight less than 1,000 Daltons,less than 800 Daltons, less than 600 Daltons, or less than 400 Daltons.A polyalkenyl can comprise a polyalkenyl-terminated prepolymer, apolyalkenyl monomer, or a combination thereof. A polyalkenyl can have,for example, 2, 3, 4, 5, or 6 terminal alkenyl groups. A polyalkenyl cancomprise a bis(alkenyl) ether, a poly(alkenyl) ether, asulfur-containing bis(alkenyl) ether, a sulfur-containing poly(alkenyl)ether, a urethane/urea-containing bis(alkenyl) ether, a urethane/ureacontaining poly(alkenyl) ether, or a combination of any of theforegoing. A poly(alkenyl) ether refers to an alkenyl the having morethan two terminal alkenyl groups such as from 3 to 6 terminal alkenylgroups.

A polyalkenyl can have the structure of Formula (19):

CH₂═CH—R—CH═CH₂  (19)

where R is selected from C₁₋₁₀ alkanediyl, C₅₋₁₀ cycloalkanediyl, C₆₋₂₀alkanecycloalkanediyl, C₁₋₁₀ heteroalkanediyl, C₅₋₁₀heterocycloalkanediyl, C₆₋₂₀ heteroalkanecycloalkanediyl, substitutedC₁₋₁₀ alkanediyl, substituted C₅₋₁₀ cycloalkanediyl, substituted C₆₋₂₀alkanecycloalkanediyl, substituted C₁₋₁₀ heteroalkanediyl, substitutedC₅₋₁₀ heterocycloalkanediyl, and substituted C₆₋₂₀heteroalkanecycloalkanediyl.

A polyalkenyl can have more than two terminal alkenyl groups and can be,for example, any of the alkenyl-terminated polyfunctionalizing agentsdisclosed herein.

A polyalkenyl can comprise a bis(alkenyl) ether. Compositions providedby the present disclosure can comprise a bis(alkenyl)ether or acombination of bis(alkenyl)ethers.

A bis(alkenyl)ether can have the structure of Formula (3):

CH₂═CH—O—(—R²—O—)_(m)—CH═CH₂  (3)

-   -   wherein,        -   m is 0 to 50; and        -   each R² can independently be C₂₋₆ n-alkanediyl, C₃₋₆            branched alkanediyl, C₆₋₈ cycloalkanediyl, C₆₋₁₀            alkanecycloalkanediyl, or            —[(—CH₂—)_(p)—O—]_(q)—(—CH₂—)_(r)—, wherein,        -   each p is independently an integer ranging from 2 to 6;        -   q is an integer from 1 to 5; and        -   r is an integer from 2 to 10.

In bis(alkenyl)ethers of Formula (3), m can be an integer from 0 to 50,such as an integer from 1 to 6, from 1 to 4, or from 1 to 3.

In bis(alkenyl)ethers of Formula (3), m can be 1, 2, 3, 4, 5, or 6.

In bis(alkenyl)ethers of Formula (3), each R² can independently be C₂₋₆alkanediyl such as 1,2-ethane-diyl, 1,3-propane-diyl, 1,4-butane-diyl,1,5-pentane-diyl, or 1,6-hexane-diyl.

In bis(alkenyl)ethers of Formula (3), each R² can be—[(—CH₂—)_(p)—O—]_(q)—(—CH₂—)_(r)—.

In bis(alkenyl)ethers of Formula (3), each R² can be—[(—CH₂—)_(p)—O—]_(q)—(—CH₂—)_(r)—, where each p can be 2, each r can be2, and q can be 1, 2, 3, 4, or 5.

Examples of suitable bis(alkenyl)ethers include divinyl ether, ethyleneglycol divinyl ether (EG-DVE), butanediol divinyl ether (BD-DVE),hexanediol divinyl ether (HD-DVE), diethylene glycol divinyl ether(DEG-DVE), triethylene glycol divinyl ether (TEG-DVE), tetraethyleneglycol divinyl ether, and cyclohexanedimethanol divinyl ether.

Suitable bis(alkenyl)ethers include, for example, compounds having atleast one oxyalkanediyl group, such as from 1 to 4 oxyalkanediyl groups,i.e., compounds in which m in Formula (3) is an integer from 1 to 4. InFormula (3), m can be an integer ranging from 2 to 4. It is alsopossible to employ commercially available divinyl ether mixtures thatare characterized by a non-integer average value for the number ofoxyalkanediyl units per molecule. Thus, m in Formula (3) can also takeon rational number values, for example, ranging from 0 to 10.0, such asfrom 1.0 to 10.0, from 1.0 to 4.0, from 2.0 to 4.0 or from 2.1 to 3.9.

Examples of suitable bis(alkenyl)ethers include, divinyl ether, ethyleneglycol divinyl ether (EG-DVE) (R² in Formula (3) is ethanediyl and m is1), butanediol divinyl ether (BD-DVE) (R² in Formula (3) is butanediyland m is 1), hexanediol divinyl ether (HD-DVE) (R² in Formula (3) ishexanediyl and m is 1), diethylene glycol divinyl ether (DEG-DVE) (R² inFormula (3) is ethanediyl and m is 2), triethylene glycol divinyl ether(R² in Formula (3) is ethanediyl and m is 3), tetraethylene glycoldivinyl ether (TEG-DVE) (R² in Formula (3) is ethanediyl and m is 4),cyclohexanedimethanol divinyl ether, cyclohexanedimethanol divinylether, polytetrahydrofuryl divinyl ether; trivinyl ether monomers, suchas trimethylolpropane trivinyl ether; tetrafunctional ether monomers,such as pentaerythritol tetravinyl ether; and combinations of two ormore such divinyl ether monomers. A bis(alkenyl)ether may have one ormore pendant groups selected from alkyl groups, hydroxyl groups, alkoxygroups, and amino groups. A bis(alkenyl)ether can comprise an aliphaticbis(alkenyl)ether, a cycloaliphatic bis(alkenyl)ether or a combinationthereof.

Bis(alkenyl)ethers in which R² in Formula (3) is C₃₋₆ branchedalkanediyl may be prepared by reacting a polyhydroxyl compound withacetylene. Examples of bis(alkenyl)ethers of this type include compoundsin which R² in Formula (3) is an alkyl-substituted methanediyl groupsuch as —CH(CH₃)— (for example Pluriol® blends such as Pluriol®E-200divinyl ether (BASF Corporation), for which R² in Formula (3) isethanediyl and m is 3.8) or an alkyl-substituted ethanediyl (for example—CH₂CH(CH₃)— such as DPE polymeric blends including DPE-2 and DPE-3,International Specialty Products).

Other useful bis(alkenyl)ethers include compounds in which R² in Formula(3) is polytetrahydrofuryl (poly-THF) or polyoxyalkanediyl, such asthose having an average of about 3 monomer units.

A polyalkenyl can comprise a sulfur-containing bis(alkenyl)ether or acombination of sulfur-containing bis(alkenyl)ethers. Sulfur-containingbis(alkenyl) ethers are disclosed in PCT International Application No.WO 2018/085650, which is incorporated by reference in its entirety. Asulfur-containing bis(alkenyl)ether can have the structure of Formula(7a):

CH₂═CH—O—(CH₂)_(n)—Y′—R⁴—Y′—(CH₂)_(n)—O—CH═CH₂  (7a)

-   -   wherein,        -   each n is independently an integer from 1 to 4;        -   each Y′ independently comprises —O— or —S—; and        -   R⁴ can be C₂₋₆ n-alkanediyl, C₃₋₆ branched alkanediyl, C₆₋₈            cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl, or            —[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, wherein,            -   each X independently can be —O—, —S—, or —S—S—;            -   p is an integer from 2 to 6;            -   q is an integer from 1 to 5; and            -   r is an integer from 2 to 6; and        -   at least one Y′ is —S—, or R⁴ is            —[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)— and at least one X is —S—            or —S—S—.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), each n can be1, 2, 3, or 4.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), each Y′ can be—O— or each Y′ can be —S—.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), R⁴ can be C₂₋₆n-alkanediyl, such as ethane-diyl, n-propane-diyl, n-butane-diyl,n-pentane-diyl, or n-hexane-diyl.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), R⁴ can be C₂₋₆n-alkanediyl; both Y′ can be —S— or one Y′ can be —S— and the other Y′can be —O—.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —O— or each Xcan be —S—S— or at least one X can be —O— or at least one X can be—S—S—.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —S— or at leastone X can be —S—.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each p can be 2 and r can be2.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where q can be 1, 2, 3, 4, or 5.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each p can be 2, r can be 2,and q can be 1, 2, 3, 4, or 5.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —S—; each p canbe 2, r can be 2, and q can be 1, 2, 3, 4, or 5.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —O—; each p canbe 2, r can be 2, and q can be 1, 2, 3, 4, or 5.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —O—; and each Y′can be —S—.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X can be —S—; and each Y′can be —O—.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), each n can be2, each Y′ can be independently selected from —O— and —S—, and R⁴ can be—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r)—, where each X is independentlyselected from —O—, —S—, and —S—S—, p can be 2, q can be selected from 1and 2, and r can be 2.

In sulfur-containing bis(alkenyl) ethers of Formula (7a), each n can be2, each Y′ can be independently selected from —O— and —S—, and R⁴ can beC₂₋₄ alkanediyl, such as ethanediyl, n-propanediyl, or n-butanediyl.

Sulfur-containing bis(alkenyl) ethers can comprise sulfur-containingbis(alkenyl) ethers of Formula (7b), Formula (7c), Formula (7d), Formula(7e), Formula (7f), Formula (7g), Formula (7h), Formula (7i), or acombination of any of the foregoing:

CH₂═CH—O—(CH₂)₂—S—(—(CH₂)₂—O—)₂—(CH₂)₂—S—(CH₂)₂—O—CH═CH₂  (7b)

CH₂═CH—O—(CH₂)₂—S—(CH₂)₂—S—(CH₂)₂—S—(CH₂)₂—O—CH═CH₂  (7c)

CH₂═CH—O—(CH₂)₂—S—(CH₂)₂—O—(CH₂)₂—S—(CH₂)₂—O—CH═CH₂  (7d)

CH₂═CH—O—(CH₂)₂—S—(CH₂)₂—S—(CH₂)₂—O—CH═CH₂  (7e)

CH₂═CH—O—(CH₂)₂—S—(CH₂)₂—O—(CH₂)₂—O—CH═CH₂  (7f)

CH₂═CH—O—(CH₂)₂—O—(CH₂)₂—S—(CH₂)₂—O—(CH₂)₂—O—CH═CH₂  (7g)

CH₂═CH—O—(CH₂)₂—O—(CH₂)₂—S—(CH₂)₂—S—(CH₂)₂—O—(CH₂)₂—O—CH═CH₂  (7h)

CH₂═CH—O—(CH₂)₂—O—(CH₂)₂—S—S—(CH₂)₂—O—(CH₂)₂—O—CH═CH₂  (7i)

Examples of suitable sulfur-containing bis(alkenyl) ethers include3,9,12,18-tetraoxa-6,15-dithiaicosa-1,19-diene,3,6,15,18-tetraoxa-9,12-dithiaicosa-1,19-diene,3,15-dioxa-6,9,12-trithiaheptadeca-1,16-diene,3,9,15-trioxa-6,12-dithiaheptadeca-1,16-diene,3,6,12,15-tetraoxa-9-thiaheptadeca-1,16-diene,3,12-dioxa-6,9-dithiatetradeca-1,13-diene,3,6,12-trioxa-9-thiatetradeca-1,13-diene,3,6,13,16-tetraoxa-9,10-dithiaoctadeca-1,17-diene, and combinations ofany of the foregoing.

A sulfur-containing bis(alkenyl) ether provided by the presentdisclosure can be liquid at room temperature. A sulfur-containingbis(alkenyl) ether can have an number average molecular weight from 200Daltons to 2,000 Daltons, from 200 Daltons to 1,500 Daltons, from 200Daltons to 1,000 Daltons, from 200 Daltons to 800 Daltons, or from 300Daltons to 500 Daltons, where the number average molecular weight isbased on the molecular structure.

The synthesis of sulfur-containing bis(alkenyl)ethers is disclosed, forexample, in PCT Application Publication No. 2018/085650, which isincorporated by reference in its entirety.

Sulfur-containing bis(alkenyl) ethers of Formula (7a) are difunctional.Sulfur-containing alkenyl ethers provided by the present disclosure canalso include sulfur-containing polyalkenyl ethers having a functionalitygreater than two, such as a functionality from 3 to 6. Also,poly(alkenyl) ethers provided by the present disclosure can also includepoly(alkenyl) ethers having a functionality greater than two, such as afunctionality from 3 to 6.

For example, a sulfur-containing poly(alkenyl) ether or poly(alkenyl)ether can have the structure of Formula (7j):

B(-V′-R¹⁰)_(z)  (7j)

-   -   wherein,        -   B comprises a core of a z-valent polyfunctionalizing agent            B(-V)_(z);        -   z is an integer from 3 to 6; and        -   each -V′- is an organic moiety; and        -   each R¹⁰ is a moiety comprising a terminal sulfur-containing            alkenyl ether group, a terminal alkenyl ether group, or            combination thereof.

A multifunctional sulfur-containing alkenyl ether can be derived from asulfur-containing bis(alkenyl) ether of Formula (7a), by reacting asulfur-containing bis(alkenyl) ether of Formula (7a) with apolyfunctionalizing agent, where the polyfunctionalizing agent comprisesterminal groups reactive with alkenyl groups such as thiol groups. Forexample, a multifunctional alkenyl ether can be derived from abis(alkenyl) ether of Formula (3), by reacting a bis(alkenyl) ether ofFormula (3) with a polyfunctionalizing agent, where thepolyfunctionalizing agent of comprises terminal groups reactive withalkenyl groups such as thiol groups.

For example, a polyfunctional sulfur-containing poly(alkenyl) ether canhave the structure of Formula (7k):

{CH₂═CH—O—(CH₂)—Y′—R⁴—Y′—(CH₂)—O—(CH₂)₂-V¹-}_(z)B  (7k)

where n, Y′, and R⁴ are defined as in Formula (7a), z and B are definedas in Formula (2b), and -V′- can be derived from the reaction of -V withan alkenyl group.

In multifunctional sulfur-containing poly(alkenyl) ethers of Formula(7k), B(-V)_(z) can be a polythiol such as any of those disclosedherein, such as 1,2,3-propanetrithiol or isocyanurate-containingtrithiols.

Multifunctional sulfur-containing poly(alkenyl) ethers of Formula (7k)can be prepared by reacting a sulfur-containing bis(alkenyl) ether ofFormula (7a) with a thiol-terminated polyfunctionalizing agent B(-V)_(z)in the presence of a suitable catalyst such as an amine catalyst.

Similarly, multifunctional polyalkenyl ethers can have the structure ofFormula (20):

{CH₂═CH—O—(—R²—O—)_(m)(CH₂)₂-V′-}_(z)B  (20)

where m, z, R², V′ and B are defined as in Formula (3) and Formula (2b).A polyalkenyl can have an alkenyl functionality greater than 2, such asan alkenyl functionality of 3, 4, 5, or 6. Examples of suitablepolyalkenyls include1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and triallylcyanurate (2,4,6-triallyloxy-1,3,5-triazine).

Multifunctional sulfur-containing poly(alkenyl) ethers can be used toprepare sulfur-containing bis(alkenyl) ether-containing polythioetherprepolymers provided by the present disclosure. For example, thereactants can include multifunctional sulfur-containing poly(alkenyl)ethers as part of the alkenyl component. Multifunctionalsulfur-containing poly(alkenyl) ethers can be the only polyfunctionalreactant having a functionality greater than 2 or may be used incombination with an alkenyl-terminated polyfunctionalizing agent such astriallyl cyanurate or triallylisocyanurate.

A polyalkenyl can comprise a urethane/urea-containing bis(alkenyl)etheror a combination of urethane/urea-containing bis(alkenyl)ethers.Urethane/urea-containing bis(alkenyl) ethers are disclosed in PCTInternational Application No. U.S. Application Publication No.2017/0368737, which is incorporated by reference in its entirety.

A urethane/urea-containing bis(alkenyl) ether can have the structure ofFormula (21):

CH₂═CH—O—R⁵—Y′—C(═O)—NH—R⁴—NH—C(═O)—Y′—R—O—CH═CH₂  (21)

wherein,

-   -   each Y′ independently comprises —NH— or —O—;    -   R⁴ comprises a core of a diisocyanate; and    -   each R⁵ independently comprises C₁₋₁₀ alkanediyl, C₅₋₁₀        cycloalkanediyl, or C₆₋₂₀ cycloalkane-alkanediyl.

In urethane/urea-containing bis(alkenyl) ethers of Formula (21), each Y′can be —O—, each Y′ can be —NH—, or one Y′ can be —O— and one Y′ can be—NH—.

In urethane/urea-containing bis(alkenyl) ethers of Formula (21), R⁵ canbe C₂₋₆ n-alkanediyl, such as ethane-diyl, n-propane-diyl,n-butane-diyl, n-pentane-diyl, or n-hexane-diyl.

In urethane/urea-containing bis(alkenyl) ethers of Formula (21), R⁵ canbe C₂₋₆ n-alkanediyl; both Y′ can be —O—, both Y′ can be —NH— or one Y′can be —NH— and the other Y′ can be —O—.

A urethane/urea-containing bis(alkenyl) ether provided by the presentdisclosure can be liquid at room temperature. A urethane/urea-containingbis(alkenyl) ether can have an number average molecular weight from 200Daltons to 2,000 Daltons, from 200 Daltons to 1,500 Daltons, from 200Daltons to 1,000 Daltons, from 200 Daltons to 800 Daltons, or from 300Daltons to 500 Daltons.

Urethane/urea-containing bis(alkenyl) ethers can be prepared by reactinga diisocyanate with a hydroxyl vinyl ether, an amino vinyl ether, or acombination of a hydroxyl vinyl ether and an amino vinyl ether.

For example, a urethane/urea-containing bis(alkenyl) ether can comprisereaction products of reactants comprising:

-   -   (a) a diisocyanate having the structure of Formula (22):

O═C═N—R⁴—N═C═O  (22)

-   -   -   where R⁴ comprises a core of a diisocyanate; and

    -   (b) a vinyl ether having the structure of Formula (23):

CH₂═CH—O—R⁵—Y  (23)

-   -   -   wherein,            -   Y is selected from —OH and —NH₂; and            -   R⁵ comprises C₁₋₁₀ alkanediyl, C₅₋₁₀ cycloalkanediyl, or                C₆₋₂₀ cycloalkane-alkanediyl.

In compounds of Formula (23), Y can be —NH₂, or Y can be —OH.

In compounds of Formula (23), R⁴ can comprise the core of an aliphaticisocyanate.

In compounds of Formula (23), R⁵ can be methane-diyl, ethane-diyl,butane-diyl, or pentane-diyl.

In compounds of Formula (23), R⁵ can be cyclopentane-diyl orcylcohexane-diyl.

Urethane/urea-containing bis(alkenyl)ethers can be prepared by reactinga diisocyanate with a hydroxyl vinyl ether of Formula (22) where Y is—OH, an amino vinyl ether of Formula (23) where Y is —NH₂, or acombination of a hydroxyl vinyl ether of Formula (22) and an amino vinylether of Formula (23).

Urethane/urea-containing bis(alkenyl) ethers can be prepared by reactinga diisocyanate with a hydroxyl vinyl ether and/or amino vinyl ether inthe presence of a tin catalyst such as dibutyl tin dilaurate.

Urethane/urea-containing bis(alkenyl) ethers of Formula (21) aredifunctional. Urethane/urea-containing bis(alkenyl) ethers provided bythe present disclosure also include multifunctionalurethane/urea-containing bis(alkenyl) ethers having an alkenylfunctionality greater than two, such as an alkenyl functionality from 3to 6.

For example, a urethane/urea-containing bis(alkenyl) ether can have thestructure of Formula (26):

B(-V¹—R⁶)_(z)  (26)

wherein,

-   -   B comprises a core of a z-valent the polyalkenyl ether;    -   z is an integer from 3 to 6;    -   each -V′- is an organic moiety; and    -   each R⁶ comprises a terminal urethane/urea-containing        bis(alkenyl) ether group.

In a polyalkenyl ether of Formula (26), -V′- can be derived from thereaction of a polyfunctionalizing agent B(-V)_(z) where V comprises aterminal group reactive with an alkenyl group such as a thiol group.

In polyalkenyl ethers of Formula (26), each R⁶ can independentlycomprise a moiety of Formula (27):

CH₂═CH—O—R⁵—Y′—C(═O)—NH—R⁴—NH—C(═O)—Y′—R—O—(CH₂)₂—  (27)

where Y′, R⁴, and R⁵, are defined as for Formula (8a).

A multifunctional urethane/urea-containing bis(alkenyl) ether can bederived from a urethane/urea-containing bis(alkenyl) ether of Formula(8), for example, by reacting a urethane/urea-containing bis(alkenyl)ether of Formula (8a) with a polyfunctionalizing agent of Formula (1):

B(-V)_(z)  (1)

For example, a polyfunctional urethane/urea-containing bis(alkenyl)ether can have the structure of Formula (28):

{CH₂═CH—O—R⁵—Y′—C(═O)—NH—R⁴—NH—C(═O)—Y′—R⁵—O—(CH₂)₂-V′-}_(z)B  (28)

where Y′, R⁴, and R⁵ are defined as in Formula (28), z and B are definedas in Formula (1), and V′ can be derived from the reaction of V with analkenyl group —CH═CH₂.

In multifunctional urethane/urea-containing bis(alkenyl) ethers ofFormula (28), B(-V)_(z) can be a polythiol such as any of thosedisclosed herein, such as 1,2,3-propane trithiol andisocyanurate-containing trithiols.

Multifunctional urethane/urea-containing bis(alkenyl) ethers of Formula(28) can be prepared by reacting a urethane/urea-containing bis(alkenyl)ether of Formula (21) with a thiol-terminated polyfunctionalizing agentB(-V)_(z) in the presence of a suitable catalyst such as an aminecatalyst.

A polyfunctional urethane/urea containing bis(alkenyl) ether can alsohave the structure of Formula (28a), Formula (28b), or a combinationthereof:

{CH₂═CH—O—R⁵—Y′—C(═O)—NH—R⁴—NH—C(═O)—Y′—R⁵—O—(CH₂)₂-V′-}_(z-w)B{-V}_(w)  (28a)

{CH₂═CH—O—R⁵—Y′—C(═O)—NH—R⁴—NH—C(═O)—Y′—R⁵—O—(CH₂)₂-V′-}_(z-w)B{-V′—(CH₂)₂—O—(—R²—O—)_(m)—CH═CH₂}_(w)  (28b)

wherein Y′, R⁴, R⁵, V, V′, R², and m are defined as for Formula (21) andFormula (1), and w is an integer from 1 to z−1.

Compositions provided by the present disclosure can comprise a metalcomplex or combination of metal complexes capable of generating freeradicals.

Suitable metal complexes are capable of reacting with organic peroxidesat temperatures from 20° C. to 25° C. to generate free radicals.

Suitable metal complexes include metal(II) (M²⁺) and metal(III) (M³⁺)complexes. The anions can be compatible with the other components of acurable composition. For example, suitable anions include organicanions.

In the presence of a suitable organic peroxides, suitable metalcomplexes can provide a fully cured composition, for example, within 7days, within 10 days, within 14 days, within 21 days, or within 28 days.

Suitable metal complexes include metal complexes of cobalt, copper,manganese, iron, vanadium, potassium, cerium, and aluminum. Suitableligands include organic ligands.

Examples of suitable metal(II) complexes include manganese(II)bis(tetramethylcyclopentadienyl), manganese(II) 2,4-pentanedioante,manganese(II) acetylacetonate, iron(II) acetylacetonate, iron(II)trifluoromethanesulfonate, iron(II) fumarate, cobalt(II)acetylacetonate, copper(II) acetylacetonate, and combinations of any ofthe foregoing.

Examples of suitable metal(III) complexes include manganese(III)2,4-pentanedionate, manganese(III) acetylacetonate, manganese(III)methanesulfonate, iron(III)acetylacetonate, and combinations of any ofthe foregoing.

Examples of suitable metal complexes include Mn(III)(acac)₃,Mn(III)(2,2′-bipyridyl)₂(acac)₃, Mn(II)(acac)₂,V(acac)₃(2,2′-bipyridyl), Fe(III)acac)₃, and combinations of any of theforegoing.

Suitable Mn complexes can be formed with ligands including, for example,2,2′-bipyridine, 1,10-phenanthroline,1,4,7-trimethyl-4,7-triazacyclononane,1,2-bis(4,7-dimethyl-1,4,7-triazacyclononan-1-yl)-ethane,N,N,N′,N″,N′″,N′″-hexamethyltriethylenetetraamine, aceytlacetonate(acac), N,N′-bis(alicylidene)cyclohexylenediamine,5,10,15,20-tetrakisphenylporphyrin,5,10,15,20-tetrakis(4′-methoxyphenyl)porphyrin, porphyrin,6-amino-1,4,6-trimethyl-1,4-diazacycloheptane,6-dimethylamino-1,4-bis(pyridine-2-ylmethyl)-6-methyl-1,4-diazacycloheptane,1,4,6-trimethyl-6[N-pyridin-2-ylmethyl)-N-methylamino]-1,4-dizazcycloheptane,4,11-dimethyl-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane, andcombinations of any of the foregoing.

Suitable Fe complexes can be formed with ligands including, for example,1,4-deazacycloheptane-based ligands such as6-amino-1,4,6-trimethyl-1,4-diazacycloheptane,6-dimethylamino-1,4-bis(pyridine-2-ylmethyl)-6-methyl-1,4-diazacycloheptane,1,4,6-trimethyl-6[N-(pyrinin-2-ylmethyl)-N-methylamino]-1,4-diazacycloheptane,bisphendimethyl 3-methyl-9-oxo-2, and4-dipyridin-2-yl-7-(pyridin-2-ylmethyl)-3,7-diazbicyclo[3.3.1]nonane-1,3-dicarboxylate;and ferrocene based ligands such as ferrocene, acylferrocene,benzeneacycloferrocene, andN,N-bis(pyridin-2-ylmethyl)-1,1-bis(pyridine-2-yl)-1-amino-ethane; andcombinations of any of the foregoing.

Suitable metal complexes can be trivalent or tetravalent.

The ligand of the metal complex can be selected to improve the storagestability of a formulation containing the metal complex. Metal complexeswith an acetylacetonate ligand are observed to be storage stable.

Curable compositions provided by the present disclosure can comprise,for example, from 0.01 wt % to 3 wt %, metal complex, from 0.05 wt % to2.5 wt %, from 0.1 wt % to 2 wt %, or from 0.5 wt % to 1.5 wt %, wherewt % is based on the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise anorganic peroxide or combination of organic peroxides.

Examples of suitable organic peroxides include ketone peroxides, diacylperoxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkylperesters, and percarbonates.

Suitable organic peroxides include tert-butyl peroxide, cumenehydroperoxide, p-menthane hydroperoxide, di-tert-butyl peroxide,tert-butylcumyl peroxide, acetyl peroxide, isobutyryl peroxide, octanoylperoxide, dibenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, andtert-butyl peroxyisobutyrate. Additional examples of suitable organicperoxides include benzoyl peroxide, tert-butyl perbenzoate,o-methylbenzoyl peroxide, p-methylbenzoyl peroxide, di-tert-butylperoxide, dicumyl peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(tert-butylperoxy)cyclohexane,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 1,6-bis(p-toluoylperoxycarbonyloxy)hexane, di(4-methylbenzoyl peroxy)hexamethylenebis-carbonate, tert-butylcumyl peroxide, methyl ethyl ketone peroxide,cumene hydroperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane,2,5-dimethyl-2,5-di(benzoylperoxy)hexane,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane,1,3-bis(t-butylperoxypropyl)benzene,di-tert-butylperoxy-diisopropylbenzene, tert-butylperoxybenzene,2,4-dichlorobenzoyl peroxide, 1,1-dibutylperoxy-3,3,5-trimethylsiloxane,n-butyl-4,4-di-tert-butyl peroxyvalerate, and combinations of any of theforegoing.

Examples of suitable organic peroxides include3,3,5,7,7-pentamethyl-1,2,4-trioxepane,2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, di-tert-butyl peroxide,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl cumyl peroxide,di(tert-butylperoxyisopropyl)benzene, dicumyl peroxide, butyl4,4-di(tert-butylperoxy)valerate, tert-butylperoxy 2-ethylhexylcarbonate, 1,1-di(tert-butylperoxy-3,3,5-trimethylcyclohexane,tert-butyl peroxybenzoate, di(4-methylbenzoyl) peroxide, dibenzoylperoxide, and di(2,4-dichlorobenzoyl) peroxide, which are commerciallyavailable, for example, from AkzoNobel.

Compositions provided by the present disclosure can also contain a metalsalt, such as, for example, Fe(II) sulfate heptahydrate orMn(III)-stearate.

Curable compositions provided by the present disclosure can comprise,for example, from 0.2 wt % to 3 wt % of an organic peroxide, from 0.5 wt% to 3 wt %, from 0.7 wt % to 2.5 wt %, from 0.1 wt % to 2 wt %, from0.2 wt % to 2 wt %, or from 0.2 wt % to 1 wt %, where wt % is based onthe total weight of the curable composition.

Metal complexes and organic peroxides can be provided in dilutesolutions of a solvent. For example the solutions can comprise from 1 wt% to 15 wt %, or from 5 wt % to 15 wt % of the metal complex or organicperoxide. Examples of solvents include acetylacetone, HB-40®(combination of terphenyls), toluene, water, isopropanol, methyl propylketone, hexanes, methanol, and cyclohexane.

The solvent can influence the application/gelation time and the curingtime of a curable composition. For example in Fe(III)(acetylacetonate)₃and Mn(III)(acetylacetonate)₃ systems, increasing the ratio of tolueneto acetylacetonate in the solution can make the metal center moreavailable for reaction by shifting the equilibrium in a direction wherethe ligand(s) can leave more easily. This mechanism should also beapplicable with other ligand and metal-ligand complexes such as2-ethylhexanoic acid and cobalt(II)bis(2-ethylhexanoate). Thus, by usingdifferent metals, organic anions, and solvent compositions, the curetime and the application time can be selected for dual cure systems.

Suitable solvents can have, for example, a polarity similar to that oftoluene. Suitable solvents include, for example, toluene, o-xylene,cyclohexane, diethyl ether, methyl-tert-butyl ether, hexane, and ethylacetate.

Suitable organic peroxides include those commercially available underthe tradename Trigonox®, Butanox®, and Perkodox® from AkzoNobel, and,under the tradename Cadox® from Summit Composites Pty, Ltd.

Curable compositions provided by the present disclosure may not includean amine catalyst. An amine catalyst can reduce the tack free time. Anamine catalyst can be selected to reduce the tack free time withoutcompromising or negatively modifying the dark cure profile. An aminecure modifier can include a primary amine, a secondary amine, a tertiaryamine or a combination of any of the foregoing.

Examples of suitable amine cure modifiers includedithethyltoluenediamene, p-toluidine,N-(2-hydroxyethyl)-N-methyl-p-toluidine (MHPT), p-tolyldiethanolamine(TDEA), Ethacure® 300 (dimethylthiotoluenediamine andmonomethylthiotoluenediamine), Ethacure® 100(3,5-dimethylthio-2,4-toluenediamine.3,5-dimethylthio-2,6-toluenediamine, and dialkylatedm-phenylenediamines), p-tolyldiethanol amine, triethanolamine,4,N,N′-trimethylaniline, N,N-dimethyl-para-p-toluidine,N,N-diisopropylethylamine, N,N,N′,N″,N′″-pentamethyl-diethylenetriamine,tris(2-pyridylmethyl)amine, N-(2-hydroxyethyl)-N-methyl-p-toluidine,dihydroxyethyl, N,N-diethyltoluene-2,5-diamine, and combinations of anyof the foregoing.

Examples of suitable primary amines include, for example, C₃₋₁₀aliphatic primary amines.

Examples of suitable secondary amines include, for example,cycloaliphatic diamines such as Jefflink® 754 and aliphatic diaminessuch as Clearlink® 1000

Examples of suitable tertiary amines include aromatic tertiary aminessuch as toluene-based tertiary amines. Examples of suitable tertiaryamines include for example, N,N-dimethylethanolamine (DMEA),diaminobicyclooctane (DABCO), triethylene diamine (TEDA),bis(2-dimethylaminoethyl)ether (BDMAEE), N-ethylmorpholine,N′,N′-dimethylpiperazine, N,N,N′,N′,N″-pentamethyl-diethylene-triamine(PMDETA), N,N′-dimethylcyclohexylamine (DMCHA), N,N-dimehtylbenzylamine(DMBA), N,N-dimethylcethylamine,N,N,N′,N″,N″-pentamethyl-dipropylene-triamine (PMDPTA), triethylamine,and 1-(2-hydroxypropyl) imidazole.

Examples of other amine cure modifiers include triethylamine (TEA),dimethylcyclohexylamine (DMCHA), tetramethylethylenediamine,tetramethylpropanediamine, tetramethylhexamethylenediamine,pentamethyldiethylenetriamine, pentamethyldipropylenetriamine,triethylendiamine (TEDA, DABCO), dimethylpiperazine,dimethylaminoethylmethylpiperazine, 1,2-dimethylimidiazole,N-ethylmorpholine, tris(dimethylaminopropyl)hexahydro-1,3-5-triazine,diazabicyclo octane (DABCO), N-alkyl morpholines (NAMs), amidines suchas tetramethylguanidine (TMG), diazabicyclononene (DBN), diazabicycloundecene (DBU) and imidazoles; and bicyclic guanidines such as1,5,7,-triazabicyclo[4.4.0]dec-5-ene (TBD) and1,5,7,-triazabicyclo[4.4.0]dec-5-ene, 7-methyl (MTBD).

An example of an amine synergist includes Ce(NH₄)(NO₃)₆.

Other cure modifiers can be used. For example, suitable cure modifiersinclude Butonox® P-50, ammonium persulfate, Borchi® OXY-coat 1310,potassium Hex-cem®, Poly-cure® 503 and FirstCure® MHPT. Examples ofsuitable cure modifiers are available from Borchers.

Fillers such as silica gel can also affect the curing profile of asealant. Other fillers that are sensitive to actinic radiation and thatcan affect the curing profile include silica and alumina.

Curable compositions provided by the present disclosure can include oneor more materials to modify the application time, the tack free timeand/or the surface tackiness of the composition. The application time,the tack free time and/or the surface tackiness of the composition canbe controlled or modified by incorporating, for example, a dark curesynergist, a dark cure co-catalyst, a singlet oxygen scavenger, ahydrogen (abstraction) donor, filler, or a combination of any of theforegoing. Compositions provided by the present disclosure can include,for example, from 0.01 wt % to 5 wt %, from 0.01 wt % to 3 wt %, from0.01 wt % to 2 wt %, from 0.01 wt % to 1 wt %, or from 0.05 wt % to 1 wt% of such cure profile modifiers.

Examples of suitable dark cure synergists include hydrogen donors suchas primary amines and secondary amines.

Examples of compounds that can modify the tack free time include stearicacid and -vinyl-2-norbornene, and combinations thereof.

Examples of suitable free radical scavengers include 2,5-diphenylfuran.

Examples of suitable singlet oxygen scavengers include ascorbic acid andFe(II).

Examples of suitable hydrogen donors include primary amines, secondaryamines, alcohols, hydroxyl-containing compounds, and combinations of anyof the foregoing.

Curable compositions can comprise a solvent. The selection and amount ofsolvent in a dual cure sealant composition provided by the presentdisclosure can influence the tack free time. As solvent evaporates forthe surface of a layer of sealant, the evaporating solvent can depletethe oxygen at the surface and therefore decrease the tack free time. Ingeneral, the use of volatile solvents can reduce the tack free time.

Curable compositions provided by the present disclosure can comprise ahydroxyl-functional vinyl ether or combination of hydroxyl-functionalvinyl ethers.

A hydroxyl-functional vinyl ether can have the structure of Formula(29):

CH₂═CH—O—(CH₂)_(t)—OH  (29)

where t is an integer from 2 to 10. In hydroxyl-functional vinyl ethersof Formula (29), t can be 1, 2, 3, 4, 5, or t can be 6. Examples ofsuitable hydroxyl-functional vinyl ethers include1-methyl-3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, and acombination thereof. A hydroxyl-functional vinyl ether can be4-hydroxybutyl vinyl ether.

Curable compositions provided by the present disclosure can comprise,for example, from 0.1 wt % to 10 wt % of a hydroxyl-functional vinylether, from 0.2 wt % to 9 wt %, from 0.3 wt % to 0.7 wt % and from 0.4wt % to 0.7 wt %, where wt % is based on the total weight of the curablecomposition.

Curable compositions provided by the present disclosure can comprise anamino-functional vinyl ether or combination of amino-functional vinylethers.

A amino-functional vinyl ether can have the structure of Formula (30):

CH₂═CH—O—(CH₂)_(t)—NH₂  (30)

where t is an integer from 2 to 10. In amino-functional vinyl ethers ofFormula (30), t can be 1, 2, 3, 4, 5, or t can be 6. Examples ofsuitable amino-functional vinyl ethers include 1-methyl-3-aminopropylvinyl ether, 4-aminobutyl vinyl ether, and a combination of any of theforegoing. A amino-functional vinyl ether can be 4-aminobutyl vinylether.

Curable compositions provided by the present disclosure can comprise,for example, from 0.1 wt % to 10 wt % of an amino-functional vinylether, from 0.2 wt % to 9 wt %, from 0.3 wt % to 0.7 wt % and from 0.4wt % to 0.7 wt %, where wt % is based on the total weight of the curablecomposition.

A curable composition can include a hydroxyl-functional vinyl ether andan amino-functional vinyl ether

Compositions provided by the present disclosure can comprise a monomericpolythiol. A monomeric dithiol can have, for example, the structure ofFormula (5).

A polythiol can comprise a polythiol having a thiol functionalitygreater than 2 such as a thiol functionality from 3 to 6, or acombination of any of the forgoing. A polythiol can comprise acombination of polythiols having an average thiol functionality greaterthan 2 such as a thiol functionality from 2.1 to 5.9, or from 2.1 to2.9.

For example, a polythiol can be trifunctional, tetrafunctional,pentafunctional, hexafunctional, or a combination of any of theforegoing. A monomeric polythiol can comprise a trithiol.

Suitable thiol-terminated monomers include, for example,mercapto-propionates, mercapto-acetates, mercapto-acrylates, and otherpolythiols.

Examples of suitable mercapto-propionates include pentaerythritoltetra(3-mercapto-propionate) (PETMP), trimethylol-propanetri(3-mercaptopropionate) (TMPMP), glycol di(3-mercaptopropionate)(GDMP), tris[2-(3-mercapto-propionyloxy)ethyl]isocyanurate (TEMPIC),di-pentaerythritol hexa(3-mercaptopropionate) (di-PETMP),tri(3-mercaptopropionate) pentaerythritol, and triethylolethanetri-(3-mercaptopropionate).

Examples of suitable thiol-terminated prepolymers include ethoxylatedtrimethylolpropane tri(3-mercaptopropionate) and polycaprolactonetetra-3-mercaptopropionate.

Examples of suitable mercapto-acetates include pentaerythritoltetramercaptoacetate (PRTMA), trimethylolpropane trimercaptoacetate(TMPMA), glycol dimercaptoacetate (GDMA), ethyleneglycoldimercaptoacetate, and di-trimethylolpropane tetramercaptoacetate.

Examples of suitable mercapto-acrylates include pentaerythritoltetra-acrylate, tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate,2,3-di(2-mercaptoethylthio)-1-propane-thiol, dimercaptodiethylsulfide(2,2′-thiodiethanethiol), dimercaptodioxaoctane(2,2′-(ethylenedioxy)diethanethiol, and 1,8-dimercapto-3,6-dioxaoctane.

Suitable thiol-terminated monomers are commercially available from BrunoBock Thiochemicals under the Thiocure® tradename.

A polythiol can comprise a polythiol of Formula (31):

B(-V)_(z)  (31)

-   -   wherein,        -   B comprises a core of a z-valent polyfunctionalizing agent            B(-V)_(z);        -   z is an integer from 3 to 6; and        -   each -V is independently a moiety comprising a terminal            thiol group.

In polythiols of Formula (31), z can be, for example, 3, 4, 5, or 6.

In polythiols of Formula (31), z can be 3. Suitable trifunctionalpolythiols include, for example, 1,2,3-propanetrithiol,isocyanurate-containing trithiols, and combinations thereof, asdisclosed in U.S. Application Publication No. 2010/0010133, and thepolythiols described in U.S. Pat. Nos. 4,366,307; 4,609,762; and5,225,472. Combinations polythiols of Formula (31) may also be used.

Other examples of suitable polythiol monomers include1,2,3-propanetrithiol, isocyanurate-containing trithiols, andcombinations thereof, as disclosed, for example, in U.S. ApplicationPublication No. 2010/0010133, which is incorporated by reference in itsentirety, and isocyanurates as disclosed, for example, in U.S.Application Publication No. 2011/0319559, which is incorporated byreference in its entirety.

Suitable thiol-terminated monomers can be characterized, for example, bya molecular weight less than 2,000 Daltons, less than 1,500 Daltons,less than 1,000 Daltons, less than 500 Daltons, or less than 250Daltons. Suitable thiol-terminated monomers can be characterized, forexample, by a weight average molecular weight from 200 Daltons to 2,000Daltons, from 200 Daltons to 1,500 Daltons, from 200 Daltons to 1000,Daltons, from 500 Daltons to 2,000 Daltons, or from 500, Daltons to1,500 Daltons. Compositions provided by the present disclosure cancomprise, for example, from 0.1 wt % to 5 wt % of a polythiol, from 0.2wt % to 3.5 wt %, from 0.5 wt % to 3 wt %, or from 1 wt % to 3 wt %, ofa polythiol, where wt % is based on the total weight of the composition.

Compositions provided by the present disclosure can comprise aplasticizer or combination of plasticizers.

Compositions can comprise a polybutadiene plasticizer. Other examples ofsuitable plasticizers include Jayflex™ DINP, Jayflex™ DIDP, Jayflex™DIUP, and Jayflex™ DTDP available from Exxon Mobil.

Compositions provided by the present disclosure can include aphotoinitiator or combination of photoinitiators. The radiation can beactinic radiation that can apply energy that can generate an initiatingspecies from a photopolymerization initiator upon irradiation therewith,and widely includes α.-rays, γ-rays, X-rays, ultraviolet (UV) lightincluding UVA, UVA, and UVC spectra), visible light, blue light,infrared, near-infrared, or an electron beam. For example, thephotoinitiator can be a UV photoinitiator.

Examples of suitable UV photoinitiators include α-hydroxyketones,benzophenone, α,α.-diethoxyacetophenone, 4,4-diethylaminobenzophenone,2,2-dimethoxy-2-phenylacetophenone, 4-isopropylphenyl 2-hydroxy-2-propylketone, 1-hydroxycyclohexyl phenyl ketone, isoamylp-dimethylaminobenzoate, methyl 4-dimethylaminobenzoate, methylO-benzoylbenzoate, benzoin, benzoin ethyl ether, benzoin isopropylether, benzoin isobutyl ether, 2-hydroxy-2-methyl-1-phenylpropan-1-one,2-isopropylthioxanthone, dibenzosuberone,2,4,6-trimethylbenzoyldiphenylphosphine oxide, bisacyclophosphine oxide.

Examples of suitable benzophenone photoinitiators include2-hydroxy-2-methyl-1-phenyl-1-propanone,2-hydroxy-1,4,4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone,α-dimethoxy-α-phenylacetophenone,2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl) phenyl]-1-butanone, and2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone.

Examples of suitable oxime photoinitiators include(hydroxyimino)cyclohexane,1-[4-(phenylthio)phenyl]-octane-1,2-dione-2-(O-benzoyloxime),1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone-1-(O-acetyloxime),trichloromethyl-triazine derivatives),4-(4-methoxystyryl)-2,6-trichloromethyl-1,3,5-triazine),4-(4-methoxyphenyl)-2,6-trichloromethyl-1,3,5-triazine, andα-aminoketone(1-(4-morpholinophenyl)-2-dimethylamino-2-benzyl-butan-1-one).

Examples of suitable phosphine oxide photoinitiators include diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide (TPO) andphenylbis(2,4,6-trimethyl benzoyl) phosphine oxide (BAPO).

Other examples of suitable UV photoinitiators include the Irgacure™products from BASF, for example the products Irgacure™ 184, Irgacure™500, Irgacure™ 1173, Irgacure™ 2959, Irgacure™ 745, Irgacure™ 651,Irgacure™ 369, Irgacure™ 907, Irgacure™ 1000, Irgacure™ 1300, Irgacure™819, Irgacure™ 819DW, Irgacure™ 2022, Irgacure™ 2100, Irgacure™ 784,Irgacure™ 250; in addition, the Irgacure™ products from BASF are used,for example the products Irgacure™ MBF, Darocur™ 1173, Darocur™ TPO,Darocur™ 4265.

A UV photoinitiator can comprise, for example,2,2-dimethoxy-1,2-diphenylethan-1-one (Irgacure® 651, Ciba SpecialtyChemicals), 2,4,6-trimethylbenzoyl-diphenyl-phosphineoxide (Darocur®TPO, Ciba Specialty Chemicals), or a combination thereof.

Other examples of suitable photoinitiators include Darocur® TPO(available from Ciba Specialty Chemicals), Lucirin® TPO (available fromBASF), Speedcure® TPO (available from Lambson), Irgacure® TPO (availablefrom Ciba Specialty Chemicals, and Omnirad® (available from IGM Resins),and combinations of any of the foregoing.

Compositions provided by the present disclosure can comprise from 1 wt %to 5 wt %, from 1.5 wt % to 4.5 wt %, from 2 wt % to 4 wt %, from 2.5 wt% to 3.5 wt % of a UV photoinitiator or combination of UVphotoinitiators, where wt % is based on the total weight of the curablecomposition.

Compositions provided by the present disclosure can comprise a filler orcombination of fillers. Suitable fillers can comprise, inorganicfillers, organic fillers, lightweight fillers, and combinations of anyof the foregoing.

Curable compositions can comprise, for example, from 15 wt % to 35 wt %filler, from 17 wt % tp 33 wt %, from 20 wt % to 30 wt % filler, or from22 wt % to 28 wt %, where wt % is based on the total weight of thecurable composition. Compositions provide by the present disclosure cancomprise, for example, silica gel, fumed silica, calcium carbonate,micronized oxidized polyethylene homopolymer, lightweight microcapsules,or a combination of any of the foregoing.

Compositions and sealants provided by the present disclosure cancomprise an organic filler or a combination of organic fillers. Organicfillers can be selected to have a low specific gravity and to beresistant to solvents such as JRF Type I. Suitable organic fillers canalso have acceptable adhesion to the sulfur-containing polymer matrix.An organic filler can include solid powders or particles, hollow powdersor particles, or a combination thereof.

An organic filler can have a specific gravity, for example, less than1.15, less than 1.1, less than 1.05, less than 1, less than 0.95, lessthan 0.9, less than 0.8, or less than 0.7. Organic fillers can have aspecific gravity, for example, within a range from 0.85 to 1.15, withina range from 0.9 to 1.1, within a range from 0.9 to 1.05, or from 0.85to 1.05.

Organic fillers can comprise thermoplastics, thermosets, or acombination thereof. Examples of suitable thermoplastics and thermosetsinclude epoxies, epoxy-amides, ETFE copolymers, nylons, polyethylenes,polypropylenes, polyethylene oxides, polypropylene oxides,polyvinylidene chlorides, polyvinylfluorides, TFE, polyamides,polyimides, ethylene propylenes, perfluorohydrocarbons, fluoroethylenes,polycarbonates, polyetheretherketones, polyetherketones, polyphenyleneoxides, polyphenylene sulfides, polystyrenes, polyvinyl chlorides,melamines, polyesters, phenolics, epichlorohydrins, fluorinatedhydrocarbons, polycyclics, polybutadienes, polychloroprenes,polyisoprenes, polysulfides, polyurethanes, isobutylene isoprenes,silicones, styrene butadienes, liquid crystal polymers, and combinationsof any of the foregoing.

Examples of suitable organic fillers include polyamides, polyimides,polyethylene, polyphenylene sulfides, and combinations of any of theforegoing.

Examples of suitable polyamide 6 and polyamide 12 particles areavailable from Toray Plastics as grades SP-500, SP-10, TR-1, and TR-2.Suitable polyamide powders are also available from the Arkema Groupunder the tradename Orgasol®, and from Evonik Industries under thetradename Vestosin®.

Examples of suitable polyimide powders are available from EvonikIndustries under the tradename P84®.

An organic filler can include a polyethylene powder, such as an oxidizedpolyethylene powder. Suitable polyethylene powders are available fromHoneywell International, Inc. under the tradename ACumist®, from INEOSunder the tradename Eltrex®, and Mitsui Chemicals America, Inc. underthe tradename Mipelon™.

The use of organic fillers such as polyphenylene sulfide in aerospacesealants is disclosed in U.S. Pat. No. 9,422,451, which is incorporatedby reference in its entirety. Polyphenylene sulfide is a thermoplasticengineering resin that exhibits dimensional stability, chemicalresistance, and resistance to corrosive and high temperatureenvironments. Polyphenylene sulfide engineering resins are commerciallyavailable, for example, under the tradenames Ryton® (Chevron), Techtron®(Quadrant), Fortron® (Celanese), and Torelina® (Toray). Polyphenylenesulfide resins are generally characterized by a specific gravity fromabout 1.3 to about 1.4.

An organic filler can have any suitable shape. For example, an organicfiller can comprise fractions of crushed polymer that has been filteredto selected a desired size range. An organic filler can comprisesubstantially spherical particles. Particles can be solid or can beporous.

An organic filler can have an average particle size, for example, withina range from 1 μm to 100 μm, 2 μm to 40 μm, from 2 μm to 30 μm, from 4μm to 25 um, from 4 μm to 20 μm, from 2 m to 12 μm, or from 5 μm to 15μm. An organic filler can have an average particle size, for example,less than 100 μm, less than 75 μm, less than 50 μm, less than 40 μm, orless than 20 μm. Particle size distribution can be determined using aFischer Sub-Sieve Sizer or by optical inspection.

An organic filler can include a low density such as a modified expandedthermoplastic microcapsules. Suitable modified expanded thermoplasticmicrocapsules can include an exterior coating of a melamine orurea/formaldehyde resin.

Compositions and sealants provided by the present disclosure cancomprise an inorganic filler or combination of inorganic fillers. Aninorganic filler can be included to provide mechanical reinforcement andto control the rheological properties of the composition. Inorganicfillers may be added to compositions to impart desirable physicalproperties such as, for example, to increase the impact strength, tocontrol the viscosity, or to modify the electrical properties of a curedcomposition. Inorganic fillers useful in compositions provided by thepresent disclosure and useful for aviation and aerospace applicationsinclude carbon black, calcium carbonate, precipitated calcium carbonate,calcium hydroxide, hydrated alumina (aluminum hydroxide), fumed silica,silica, precipitated silica, silica gel, and combinations of any of theforegoing. For example, an inorganic filler can include a combinationcalcium carbonate and fumed silica, and the calcium carbonate and fumedsilica can be treated and/or untreated.

An inorganic filler can be coated or uncoated. For example, an inorganicfiller can be coated with a hydrophobic coating, such as a coating ofpolydimethylsiloxane.

Compositions provided by the present disclosure can comprise, forexample, from 5 wt % to 25 wt % of an inorganic filler or combination ofinorganic fillers, from 7 wt % to 23 wt %, from 10 wt % to 20 wt %, orfrom 12 wt % to 18 wt %, where wt % is based on the total weight of thecomposition.

Compositions provided by the present disclosure can comprise silica gelor combination of silica gel. Suitable silica gel include Gasil® silicagel available from PQ Corporation, and Sylysia®, CariAct® and Sylomask®silica gel available from Fuji Silysia Chemical Ltd. Compositionsprovided by the present disclosure can comprise, for example, from 5 wt% to 25 wt %, from 10 wt % to 20 wt %, or from 12 wt % to 18, of silicagel, where wt % is based on the total weight of the curable composition.

Compositions provided by the present disclosure can comprise low densitymicrocapsules. A low density microcapsule can comprise a thermallyexpandable microcapsule.

A thermally expandable microcapsule refers to a hollow shell comprisinga volatile material that expands at a predetermined temperature.Thermally expandable thermoplastic microcapsules can have an averageinitial particle size of 5 μm to 70 μm, in some cases 10 μm to 24 μm, orfrom 10 μm to 17 μm. The term “average initial particle size” refers tothe average particle size (numerical weighted average of the particlesize distribution) of the microcapsules prior to any expansion. Theparticle size distribution can be determined using a Fischer Sub-SieveSizer or by optical inspection.

A thermally expandable thermoplastic microcapsule can comprise avolatile hydrocarbon within a wall of a thermoplastic resin. Examples ofhydrocarbons suitable for use in such microcapsules are include methylchloride, methyl bromide, trichloroethane, dichloroethane, n-butane,n-heptane, n-propane, n-hexane, n-pentane, isobutane, isopentane,iso-octane, neopentane, petroleum ether, and aliphatic hydrocarbonscontaining fluorine, such as Freon™, and combinations of any of theforegoing.

Examples of materials suitable for forming the wall of a thermallyexpandable microcapsule include polymers of vinylidene chloride,acrylonitrile, styrene, polycarbonate, methyl methacrylate, ethylacrylate, and vinyl acetate, copolymers of these monomers, andcombinations of the polymers and copolymers. A crosslinking agent may beincluded with the materials forming the wall of a thermally expandablemicrocapsule.

Examples of suitable thermoplastic microcapsules include Expancel™microcapsules such as Expancel™ DE microspheres available fromAkzoNobel. Examples of suitable Expancel™ DE microspheres includeExpancel™ 920 DE 40 and Expancel™ 920 DE 80. Suitable low densitymicrocapsules are also available from Kureha Corporation.

Suitable low density filler such as low density microcapsules can have amean diameter (d0.5), for example, from 1 μm to 100 μm, from 10 μm to 80μm, or from 10 μm to 50 μm, as determined according to ASTM D1475.

Low density filler such as low density microcapsules can becharacterized by a specific gravity within a range from 0.01 to 0.09,from 0.04 to 0.09, within a range from 0.04 to 0.08, within a range from0.01 to 0.07, within a range from 0.02 to 0.06, within a range from 0.03to 0.05, within a range from 0.05 to 0.09, from 0.06 to 0.09, or withina range from 0.07 to 0.09, wherein the specific gravity is determinedaccording to ASTM D1475. Low density filler such as low densitymicrocapsules can be characterized by a specific gravity less than 0.1,less than 0.09, less than 0.08, less than 0.07, less than 0.06, lessthan 0.05, less than 0.04, less than 0.03, or less than 0.02, whereinthe specific gravity is determined according to ASTM D1475.

Low density filler such as low microcapsules can be characterized by amean particle diameter from 1 μm to 100 μm and can have a substantiallyspherical shape. Low density filler such as low density microcapsulescan be characterized, for example, by a mean particle diameter from 10 mto 100 μm, from 10 μm to 60 μm, from 10 μm to 40 μm, or from 10 μm to 30μm, as determined according to ASTM D1475.

Low density filler can comprise uncoated microcapsules, coatedmicrocapsules, or combinations thereof.

Low density filler such as low density microcapsules can compriseexpanded microcapsules or microballoons having a coating of anaminoplast resin such as a melamine resin. Aminoplast resin-coatedparticles are described, for example, in U.S. Pat. No. 8,993,691, whichis incorporated by reference in its entirety. Such microcapsules can beformed by heating a microcapsule comprising a blowing agent surroundedby a thermoplastic shell. Uncoated low density microcapsules can bereacted with an aminoplast resin such as a urea/formaldehyde resin toprovide a coating of a thermoset resin on the outer surface of theparticle.

Low density filler such as low density microcapsules can comprisethermally expandable thermoplastic microcapsules having an exteriorcoating of an aminoplast resin, such as a melamine resin. The coated lowdensity microcapsules can have an exterior coating of a melamine resin,where the coating can have a thickness, for example, less than 2 μm,less than 1 μm, or less than 0.5 μm. The melamine coating on the lightweight microcapsules is believed to render the microcapsules reactivewith the thiol-terminated polythioether prepolymer and/or thepolyepoxide curing agent, which enhances the fuel resistance, andrenders the microcapsules resistant to pressure.

The thin coating of an aminoplast resin can have a film thickness ofless than 25 μm, less than 20 μm, less than 15 μm, or less than 5 μm.The thin coating of an aminoplast resin can have a film thickness of atleast 0.1 nanometers, such as at least 10 nanometers, or at least 100nanometers, or, in some cases, at least 500 nanometers.

Aminoplast resins can be based on the condensation products offormaldehyde, with an amino- or amido-group carrying substance.Condensation products can be obtained from the reaction of alcohols andformaldehyde with melamine, urea or benzoguanamine. Condensationproducts of other amines and amides can also be employed, for example,aldehyde condensates of triazines, diazines, triazoles, guanidines,guanamines and alkyl- and aryl-substituted derivatives of suchcompounds, including alkyl- and aryl-substituted ureas and alkyl- andaryl-substituted melamines. Examples of such compounds includeN,N′-dimethyl urea, benzourea, dicyandiamide, formaguanamine,acetoguanamine, glycoluril, ammeline,2-chloro-4,6-diamino-1,3,5-triazine,6-methyl-2,4-diamino-1,3,5-triazine, 3,5-diaminotriazole,triaminopyrimidine, 2-mercapto-4,6-diaminopyrimidine and3,4,6-tris(ethylamino)-1,3,5 triazine. Suitable aminoplast resins canalso be based on the condensation products of other aldehydes such asacetaldehyde, crotonaldehyde, acrolein, benzaldehyde, furfural, andglyoxal.

An aminoplast resin can comprise a highly alkylated, low-iminoaminoplast resin which has a degree of polymerization less than 3.75,such as less than 3.0, or less than 2.0. The number average degree ofpolymerization can be defined as the average number of structural unitsper polymer chain. For example, a degree of polymerization of 1.0indicates a completely monomeric triazine structure, while a degree ofpolymerization of 2.0 indicates two triazine rings joined by a methyleneor methylene-oxy bridge. Degree of polymerization represents an averagedegree of polymerization value as determined by gel permeationchromatography using polystyrene standards.

An aminoplast resin can contain methylol or other alkylol groups, and atleast a portion of the alkylol groups can be etherified by reaction withan alcohol. Examples of suitable monohydric alcohols include alcoholssuch as methanol, ethanol, propanol, butanol, pentanol, hexanol,heptanol, benzyl alcohol, other aromatic alcohols, cyclic alcohols suchas cyclohexanol, monoethers of glycols, and halogen-substituted or othersubstituted alcohols, such as 3-chloropropanol and butoxyethanol.Aminoplast resins can be substantially alkylated with methanol orbutanol.

An aminoplast resin can comprise a melamine resin. Examples of suitablemelamine resins include methylated melamine resins(hexamethoxymethylmelamine), mixed ether melamine resins, butylatedmelamine resins, urea resins, butylated urea resins, benzoguanamine andglycoluril resins, and formaldehyde free resins. Such resins areavailable, for example, from Allnex Group and Hexion. Examples ofsuitable melamine resins include methylated melamine resins such asCymel™ 300, Cymel™ 301, Cymel™ 303LF, Cymel™ 303ULF, Cymel™ 304, Cymel™350, Cymel 3745, Cymel™ XW-3106, Cymel™ MM-100, Cymel™ 370, Cymel™ 373,Cymel™ 380, ASTRO MEL™601, ASTRO MEL™ 601ULF, ASTRO MEL™400, ASTRO MEL™NVV-3A, Aricel PC-6A, ASTRO MEL™ CR-1, and ASTRO SET™ 90.

A suitable aminoplast resin can comprise a urea-formaldehyde resin.

Aminoplast resin-coated particles are distinct from uncoated particlesthat are merely incorporated into a polymer network, such as is the casewhen uncoated low density particles are dispersed in a film-formingbinder. For aminoplast resin-coated particles, a thin film is depositedon the exterior surface of individual discrete particles such asthermally expanded microcapsules. These aminoplast resin-coatedparticles may then be dispersed in a film-forming binder, therebyresulting in dispersion of the coated particles throughout a polymernetwork. The thin coating of an aminoplast resin can cover, for examplefrom 70% to 100%, from 80% to 100%, or from 90% to 100% of the exteriorsurface of a low density particle such as a thermally expandedmicrocapsule. The coating of an aminoplast resin can form asubstantially continuous covering on the exterior surface of a lowdensity particle.

Low density microcapsules can be prepared by any suitable technique,including, for example, as described U.S. Pat. Nos. 8,816,023 and8,993,691, each of which is incorporated by reference in its entirety.Coated low density microcapsules can be obtained, for example, bypreparing an aqueous dispersion of microcapsules in water with amelamine resin, under stirring. A catalyst may then be added and thedispersion heated to, for example, a temperature from 50° C. to 80° C.Low density microcapsules such as thermally expanded microcapsuleshaving a polyacrylonitrile shell, de-ionized water and an aminoplastresin such as a melamine resin can be combined and mixed. A 10% w/wsolution of para-toluene sulfuric acid in distilled water can then beadded and the mixture reacted at 60° C. for about 2 hours. Saturatedsodium bicarbonate can then be added and the mixture stirred for 10minutes. The solids can be filtered, rinsed with distilled water, anddried overnight at room temperature. The resulting powder of aminoplastresin-coated microcapsules can then be sifted through a 250 μm sieve toremove and separate agglomerates.

Prior to application of an aminoplast resin coating, athermally-expanded thermoplastic microcapsule can be characterized by aspecific gravity, for example, within a range from 0.01 to 0.05, withina range from 0.015 to 0.045, within a range from 0.02 to 0.04, or withina range from 0.025 to 0.035, wherein the specific gravity is determinedaccording to ASTM D1475. For example, Expancel™ 920 DE 40 and Expancel™920 DE 80 can be characterized by a specific gravity of about 0.03,wherein the specific gravity is determined according to ASTM D1475.

Following coating with an aminoplast resin, an aminoplast-coatedmicrocapsule can be characterized by a specific gravity, for example,within a range from 0.02 to 0.08, within a range from 0.02 to 0.07,within a range from 0.02 to 0.06, within a range from 0.03 to 0.07,within a range from 0.03 to 0.065, within a range from 0.04 to 0.065,within a range from 0.045 to 0.06, or within a range from 0.05 to 0.06,wherein the specific gravity is determined according to ASTM D1475.

Compositions and sealants provided by the present disclosure can includean adhesion promoter or combination of adhesion promoters.

Curable compositions provided by the present disclosure can comprise,for example, less than 0.1 wt % of an adhesion promoter, less than 0.2wt %, less than 0.3 wt % or less than 0.4 wt % of an adhesion promoter,where wt % is based on the total weight of the curable composition. Acurable composition provided by the present disclosure can comprise, forexample from 0.05 wt % to 0.4 wt %, from 0.05 wt % to 0.3 wt %, from0.05 wt % to 0.2 wt % of an adhesion promoter.

Low density compositions provided by the present disclosure can comprisean adhesion promoter or combination of adhesion promoters. An adhesionpromoter can include a phenolic adhesion promoter, a combination ofphenolic adhesion promoters, an organo-functional silane, a combinationof organo-functional silanes, or a combination of any of the foregoing.An organosilane can be an amine-functional silane.

Compositions and sealants provided by the present disclosure cancomprise a phenolic adhesion promoter, an organosilane, or a combinationthereof. A phenolic adhesion promoter can comprise a cooked phenolicresin, an un-cooked phenolic resin, or a combination thereof. Examplesof suitable adhesion promoters include phenolic resins such as Methylon®phenolic resin, and organosilanes, such as epoxy-, mercapto- oramine-functional silanes, such as Silquest® organosilanes.

Phenolic adhesion promoters can comprise the reaction product of acondensation reaction of a phenolic resin with one or morethiol-terminated polysulfides. Phenolic adhesion promoters can bethiol-terminated.

Examples of suitable phenolic resins include 2-(hydroxymethyl)phenol,(4-hydroxy-1,3-phenylene)dimethanol, (2-hydroxybenzene-1,3,4-triyl)trimethanol, 2-benzyl-6-(hydroxymethyl)phenol,(4-hydroxy-5-((2-hydroxy-5-(hydroxymethyl)cyclohexa-2,4-dien-1-yl)methyl)-1,3-phenylene)dimethanol,(4-hydroxy-5-((2-hydroxy-3,5-bis(hydroxymethyl)cyclohexa-2,4-dien-1-yl)methyl)-1,3-phenylene)dimethanol,and a combination of any of the foregoing.

Suitable phenolic resins can be synthesized by the base-catalyzedreaction of phenol with formaldehyde.

Phenolic adhesion promoters can comprise the reaction product of acondensation reaction of a Methylon® resin, a Varcum® resin, or a Durez®resin available from Durez Corporation with a thiol-terminatedpolysulfide such as a Thioplast® resin.

Examples of Methylon® resins include Methylon® 75108 (allyl ether ofmethylol phenol, see U.S. Pat. No. 3,517,082) and Methylon® 75202.

Examples of Varcum® resins include Varcum® 29101, Varcum® 29108, Varcum®29112, Varcum® 29116, Varcum® 29008, Varcum® 29202, Varcum® 29401,Varcum® 29159, Varcum® 29181, Varcum® 92600, Varcum® 94635, Varcum®94879, and Varcum® 94917.

An example of a Durez® resin is Durez® 34071.

Compositions provided by the present disclosure can comprise anorgano-functional adhesion promoter such as an organo-functional silane.An organo-functional silane can comprise hydrolysable groups bonded to asilicon atom and at least one organofunctional group. Anorgano-functional silane can have the structureR^(a)—(CH₂)_(n)—Si(—OR)_(3-n)R^(b) _(n), where R^(a) is anorganofunctional group, n is 0, 1, or 2, and R and R^(b) is alkyl suchas methyl or ethyl. Examples of organofunctional groups include epoxy,amino, methacryloxy, or sulfide groups. An organofunctional silane canbe a dipodal silane having two or more silane groups, a functionaldipodal silane, a non-functional dipodal silane or a combination of anyof the foregoing. An organofunctional silane can be a combination of amonosilane and a dipodal silane.

An amine-functional silane can comprise a primary amine-functionalsilane, a secondary amine-functional silane, or a combination thereof. Aprimary amine-functional silane refers to a silane having primary aminogroup. A secondary amine-functional silane refers to a silane having asecondary amine group. An amine-functional silane can comprise, forexample, from 40 wt % to 60 wt % of a primary amine-functional silane;and from 40 wt % to 60 wt % of a secondary amine-functional silane; from45 wt % to 55 wt % of a primary amine-functional silane and from 45 wt %to 55 wt % of a secondary amine-functional silane; or from 47 wt % to 53wt % of a primary amine-functional silane and from 47 wt % to 53 wt % ofa secondary amine-functional silane; where wt % is based on the totalweight of the amine-functional silane in a composition.

A secondary amine-functional silane can be a sterically hinderedamine-functional silane. In a sterically hindered amine-functionalsilane the secondary amine can be proximate a large group or moiety thatlimits or restricts the degrees of freedom of the secondary aminecompared to the degrees of freedom for a non-sterically hinderedsecondary amine. For example, in a sterically hindered secondary amine,the secondary amine can be proximate a phenyl group, a cyclohexyl group,or a branched alkyl group.

Amine-functional silanes can be monomeric amine-functional silaneshaving a molecular weight, for example, from 100 Daltons to 1000Daltons, from 100 Daltons to 800 Daltons, from 100 Daltons to 600Daltons, or from 200 Daltons to 500 Daltons.

Examples of suitable primary amine-functional silanes include4-aminobutyltriethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane,N-(2-aminoethyl)-3-aminopropyltriethoxysilane,3(m-aminophenoxy)propyltrimethoxysilane, m-aminophenyltrimethoxysilane,p-aminophenyltrimethoxysilane, 3-aminopropyltriethoxysilane,3-aminopropyltrimethoxysilane,3-aminopropyltris(methoxyethoxyethoxy)silane,11-aminoundecyltriethoxysilane, 2-(4-pyridylethyl)triethoxysilane,2-(2-pyridylethyltrimethoxysilane, N-(3-trimethoxysilylpropyl)pyrrole,3-aminopropylsilanetriol,4-amino-3,3-dimethylbutylmethyldimethoxysilane,3-aminopropylmethyldiethoxysilane,1-amino-2-(dimethylethoxysilyl)propane, 3-aminopropyldiisopropyleneethoxysilane, and 3-aminopropyldimethylethoxysilane.

Examples of suitable diamine-functional silanes includeaminoethylaminomethyl)phenethyltrimethoxysilane andN-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

Examples of suitable secondary amine-functional silanes include3-(N-allylamino)propyltrimethoxysilane,n-butylaminopropyltrimethoxysilane,tert-butylaminopropyltrimethoxysilane,(N,N-cylohexylaminomethyl)methyldiethoxysilane,(N-cyclohexylaminomethyl)triethoxysilane,(N-cyclohexylaminopropyl)trimethoxysilane,(3-(n-ethylamino)isobutyl)methyldiethoxysilane,(3-(N-ethylamino)isobutyl)trimethoxysilane,N-methylaminopropylmethyldimethoxysilane,N-methylaminopropyltrimethoxysilane,(phenylaminomethyl)methyldimethoxysilane,N-phenylaminomethyltriethoxysilane, andN-phenylaminopropyltrimethoxysilane.

Suitable amine-functional silanes are commercially available, forexample, from Gelest Inc. and from Dow Corning Corporation.

Curable compositions provided by the present disclosure can compriseless than 3 wt % of an adhesion promoter, less than 2 wt %, less than 1wt % or less than 0.5 wt %, where wt % is based on the total weight ofthe curable composition.

Curable compositions provided by the present disclosure can comprise apigment, a dye, a photochromic agent, or a combination of any of theforegoing. Because a curable composition can fully cure under darkconditions, a dye, pigment, and/or photochromic agent can be used. Forcuring with actinic radiation, the surface of an applied sealant cancure and the non-exposed regions of the applied sealant can cure.

Any suitable dye, pigment, and/or photochromic agent can be used.

In certain applications it can be desirable that a photochromic agentthat is sensitive to the degree of cure be used. Such agents can providea visual indication that the sealant has been exposed to a desiredamount of actinic radiation, or example, to cure the sealant. Certainphotochromic agents can be used as cure indicators. A cure indicator canfacilitate the ability to assess the extent of cure of a sealant byvisual inspection.

A photochromic material can be a compound that is activated by absorbingradiation energy having a particular wavelength, such as UV radiation,which causes a feature change such as a color change. A feature changecan be an identifiable change in a feature of the photochromic materialwhich can be detected using an instrument or visually. Examples offeature changes include a change of color or color intensity and achange in structure or other interactions with energy in the visible UV,infrared (IR), near IR or far IR portions of the electromagneticspectrum such as absorption and/or reflectance. A color change atvisible wavelengths refers to a color change at wavelengths within arange from 400 nm to 800 nm.

A sealant composition provided by the present disclosure can include atleast one photochromic material. A photochromic material can beactivated by absorbing radiation energy (visible and non-visible light)having a particular wavelength, such as UV light, to undergo a featurechange such as a color change. The feature change can be a change offeature of the photochromic material alone or it can be a change offeature of the sealant composition. Examples of suitable photochromicmaterials include spiropyrans, spiropyrimidines, spirooxazines,diarylethenes, photochromic quinones, azobenzenes, other photochromicdyes and combinations thereof. These photochromic materials undergo areversible color change when exposed to radiation where the first andsecond colored states are different colors or different intensities ofthe same color.

Spiropyrans are photochromic molecules that change color and/orfluoresce under different wavelength light sources. Spiropyranstypically have a 2H-pyran isomer in which the hydrogen atom at positiontwo is replaced by a second ring system linked to the carbon atom atposition two of the pyran molecule in a spiro way resulting in a carbonatom that is common on both rings. The second ring is often but notexclusively heterocyclic. Examples of suitable spiropyrans include1′,3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2-,2′-(2H)-indole];1′,3′-dihydro-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-(2H)-indole];1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-[3H]naphth[2,1-b][-1,4]oxazine];6,8-dibromo-1′,3′-dihydro-1′,3′,3′-trimethylspiro[2H-1-benzopyran-2,2′-(2-H)-indole];5-chloro-1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-[3H]phenanthr[9,-10-b][1,4]oxazine];6-bromo-1′,3′-dihydro-1′,3′,3′-trimethyl-8-nitrospiro[2H-1-benzopyran-2,2′-(2H)-indole];5-chloro-1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-[3H]naphth[2,1-b-][1,4]oxazine];1′,3′-dihydro-5′-methoxy-1′,3,3-trimethyl-6-nitrospiro[2H-1-benzopyran-2,-2′(2H)-indole];1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-[3H]phenanthr[9,10-b][1,4-]oxazine];5-methoxy-1,3,3-trimethylspiro[indoline-2,3′-[3H]naphtha[2,1-b]-pyran];8′-methacryloxymethyl-3-methyl-6′-nitro-1-selenaspiro-[2H-1′-benzopyran-2,2′-benzoselenenazoline];3-isopropyl-8′-methacryloxymethyl-5-methoxy-6′-nitro-1-selenaspiro[2H-1′-benzopyran-2,2′-benzoselenazoline];3-isopropyl-8′-methacryloxymethyl-5-methoxy-6′-nitro-1-selenaspiro[2H-1′-benzopyran-2,2′-benzoselenazoline];8′-methacryloxymethyl-5-methoxy-2-methyl-6′-nitro-1-selenaspiro[2H-1′-ben-zopyran-2,2′-benzoselenazoline];2,5-dimethyl-8′-methacryloxymethyl-6′-nitro-1-selenaspiro[2H-1′-benzopyran-2,2′-benzoselenazoline];8′-methacryloxymethyl-5-methoxy-3-methyl-6′-nitrospiro[benzoselenazoline-2,2′(2′H)-1′-benzothiopyran];8-methacryloxymethyl-6-nitro-1′,3′,3′-trimethylspiro[2H-1-benzothiopyran-2,2′-indoline];3,3-dimethyl-1-isopropyl-8′-methacryloxymethyl-6′-nitrospiro-[indoline-2,-2′(2′H)-1′-benzothiopyran];3,3-dimethyl-8′-methacryloxymethyl-6′-nitro-1-octadecylspiro[indoline-2,2-′(2′H)-1′-benzothiopyran]and combinations thereof.

Azobenzenes are capable of photoisomerization between trans- andcis-isomers. Examples of suitable azobenzenes include azobenzene;4-[bis(9,9-dimethylfluoren-2-yl)amino]azobenzene;4-(N,N-dimethylamino)azobenzene-4′-isothiocyanate;2,2′-dihydroxyazobenzene; 1,1′-dibenzyl-4,4′-bipyridinium dichloride;1,1′-diheptyl-4,4′-bipyridinium dibromide;2,2′,4′-trihydroxy-5-chloroazobenzene-3-sulfonic acid and combinationsthereof.

Examples of suitable photochromicspirooxazines include1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-[3H]phenanthr[9,10-b](1,4-)oxazine];1,3,3-trimethyl spiro(indoline-2,3′-(3H)naphth(2,1-b)(1,4)oxazine);3-ethyl-9′-methoxy-1,3-dimethylspiro(indoline-2,3′-(3H)naphth(2,1-b)(1,4)-oxazine);1,3,3-trimethylspiro(indoline-2,3′-(3H)pyrido(3,2-f)-(1,4)benzoxazine);1,3-dihydrospiro(indoline-2,3′-(3H)pyrido(3,2-f)-(1,4)benzoxazine) andcombinations thereof.

Examples of suitable photochromic spiropyrimidines include2,3-dihydro-2-spiro-4′-[8′-aminonaphthalen-1′(4′H)-one]pyrimidine;2,3-dihydro-2-spiro-7′-[8′-imino-7′,8′-dihydronaphthalen-1′-amine]pyrimidineand combinations thereof.

Examples of suitable photochromic diarylethenes include2,3-bis(2,4,5-trimethyl-3-thienyl)maleic anhydride;2,3-bis(2,4,5-trimethyl-3-thienyl)maleimide;cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethane;1,2-bis[2-methylbenzo[b]thiophen-3-yl]-3,3,4,4,5,5-hexafluoro-1-cyclopent-ene;1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluoro-1-cyclopentene;stilbene; dithienylethenes and combinations thereof.

Examples of suitable photochromic quinones include1-phenoxy-2,4-dioxyanthraquinone; 6-phenoxy-5,12-naphthacenequinone;6-phenoxy-5,12-pentacenequinone;1,3-dichloro-6-phenoxy-7,12-phthaloylpyrene and combinations thereof.

Examples of suitable photochromic agents that can be used as cureindicators include ethylviolet and Disperse Red 177.

A photochromic material can produce a reversible color feature changewhen irradiated. The reversible color change can be caused by areversible transformation of the photochromic material between twomolecular forms having different absorption spectra as a result of theabsorption of electromagnetic radiation. When the source of radiation iswithdrawn or turned off, the photochromic material normally reverts backto its first color state.

A photochromic material can exhibit an irreversible color changefollowing exposure to radiation. For example, exposing the photochromicmaterial to radiation can cause the photochromic material to change froma first state to a second state. When the radiation exposure is removed,the photochromic material is prevented from reverting back to theinitial state as a result of a physical and/or chemical interaction withone or more components of the sealant composition.

A composition provided by the present disclosure can include, forexample, from 0.1 wt % to 10 wt % of a photochromic material, such asfrom 0.1 wt % to 5 wt % or from 0.1 wt % to 2 wt %, where wt % is basedon the total weight of the composition.

Compositions provided by the present disclosure may be formulated assealants. By formulated is meant that in addition to the reactivespecies forming the cured polymer network, additional material can beadded to a composition to impart desired properties to the uncuredsealant and/or to the cured sealant. For the uncured sealant theseproperties can include viscosity, pH, and/or rheology. For curedsealants, these properties can include weight, adhesion, corrosionresistance, color, glass transition temperature, electricalconductivity, cohesion, and/or physical properties such as tensilestrength, elongation, and hardness. Compositions provided by the presentdisclosure may comprise one or more additional components suitable foruse in aerospace sealants and the selection can depend at least in parton the desired performance characteristics of the cured sealant underconditions of use.

Curable compositions provided by the present disclosure can be visuallyclear. A visually clear sealant can enable visual inspection of thequality of the seal. Curable compositions can be transmissive orpartially transmissive to actinic radiation such as UV radiation. Thematerials forming a curable composition can be selected to provide adesired depth of cure following exposure to actinic radiation. Forexample, the filler used can be selected to be transmissive or partiallytransmissive to actinic radiation such as UV radiation and/or the sizeand geometry of the filler can be selected to forward scatter incidentactinic radiation.

Curable compositions provided by the present disclosure can comprise,for example, from 3 wt % to 9 wt % of a poly(alkenyl) ether, from 55 wt% to 75 wt % of a thiol-terminated sulfur-containing prepolymer, from 5wt % to 15 wt % of an inorganic filer such as fumed silica, and from 10wt % to 20 wt % of silica gel, where wt % is based on the total weightof the curable composition.

Curable compositions provided by the present disclosure can comprise,for example, from 4 wt % to 8 wt % of a polyalkenyl such as apoly(alkenyl) ether, from 60 wt % to 70 wt % of a polythiol such as athiol-terminated sulfur-containing prepolymer, from 7 wt % to 13 wt % ofan inorganic filer such as fumed silica, and from 12 wt % to 18 wt % ofsilica gel, where wt % is based on the total weight of the curablecomposition.

Curable compositions provided by the present disclosure can comprise,for example, from 5 wt % to 7 wt % of a poly(alkenyl) ether, from 63 wt% to 67 wt % of a thiol-terminated sulfur-containing prepolymer, from 8wt % to 11 wt % of an inorganic filer such as fumed silica, and from 14wt % to 16 wt % of silica gel, where wt % is based on the total weightof the curable composition.

Curable compositions provided by the present disclosure can comprise,for example, from 3 wt % to 9 wt % of a poly(alkenyl) ether, from 55 wt% to 75 wt % of a thiol-terminated sulfur-containing prepolymer, from 1wt % to 3.5 wt % of a polythiol having a thiol functionality greaterthan two, from 5 wt % to 15 wt % of an inorganic filer such as fumedsilica, and from 10 wt % to 20 wt % of a silica gel, where wt % is basedon the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise,for example, from 4 wt % to 8 wt % of a poly(alkenyl) ether, from 60 wt% to 70 wt % of a thiol-terminated sulfur-containing prepolymer, from1.3 wt % to 3.1 wt % of a polythiol, from 7 wt % to 13 wt % of aninorganic filer such as fumed silica, and from 12 wt % to 18 wt % ofsilica gel, where wt % is based on the total weight of the curablecomposition.

Curable compositions provided by the present disclosure can comprise,for example, from 5 wt % to 7 wt % of a poly(alkenyl) ether, from 63 wt% to 67 wt % of a thiol-terminated sulfur-containing prepolymer, from1.6 wt % to 2.9 wt % of a polythiol, from 8 wt % to 11 wt % of aninorganic filer such as fumed silica, and from 14 wt % to 16 wt % ofsilica gel, where wt % is based on the total weight of the curablecomposition.

Any of the foregoing curable compositions comprises a dark cure metalcomplex/organic peroxide catalyst. For example, a curable compositioncan comprise from 0.01 wt % to 3 wt % of a metal complex and from 0.2 wt% to 3 wt % of the organic peroxide, where wt % is based on the totalweight of the composition.

Curable compositions provided by the present disclosure can comprise,for example, from 1 wt % to 10 wt % of a polyalkenyl such as a divinylether, from 2 wt % to 9 wt %, from 3 wt % to 8 wt %, or from 4 wt % to 7wt % of a polyalkenyl, where wt % is based on the total weight of thecurable composition.

Curable compositions provided by the present disclosure can comprise,for example, from 0.01 wt % to 3 wt % of a hydroxy-vinyl ether, from0.05 wt % to 2.5 wt %, from 0.1 wt % to 2 wt %, or from 0.2 wt % to 1.5wt % of a hydroxy-vinyl ether, where wt % is based on the total weightof the curable composition.

Curable compositions provided by the present disclosure can comprise,for example, from 45 wt % to 85 wt % of a polythiol such as athiol-terminated prepolymer such as a thiol-terminated polythioetherprepolymer, from 50 wt % to 80 wt %, or from 60 wt % to 75 wt % of apolythiol such as a thiol-terminated prepolymer, where wt % is based onthe total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise,for example, from 0.1 wt % to 10 wt % of a polythiol having a thiolfunctionality greater than 2, from 0.5 wt % to 8 wt %, from 1 wt % to 6wt %, or from 1 wt % to 4 wt % of a polythiol having a thiolfunctionality greater than two, where wt % is based on the total weightof the curable composition.

Curable compositions provided by the present disclosure can comprise,for example, from 0.01 wt % to 2 wt % of a photoinitiator, from 0.05 wt% to 1.5 wt % of a photoinitiator, or from 0.05 wt % to 1 wt % of aphotoinitiator, where wt % is based on the total weight of the curablecomposition.

Curable compositions provided by the present disclosure can comprise,for example, from 0.01 wt % to 4 wt % of a plasticizer, from 0.05 wt %to 3 wt %, or from 0.1 wt % to 2 wt % of a plasticizer, where wt % isbased on the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise,for example, from 1 wt % to 50 wt % of a filler, from 5 wt % to 40 wt %,from 10 wt % to 30 wt %, or from 15 wt % to 25 wt % of a filler, wherewt % is based on the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise,for example, from 0.01 wt % to 3 wt % of an adhesion promoter, from 0.05wt % to 2.5 wt %, or from 0.05 wt % to 1 wt % of an adhesion promoter,where wt % is based on the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise,for example, from 0.01 wt % to 4 wt %, from 0.02 wt % to 3 wt %, from0.05 wt % to 2 wt %, or from 0.1 wt % to 1.5 wt % of an organicperoxide, where wt % is based on the total weight of the curablecomposition.

Curable compositions provided by the present disclosure can comprise,for example, from 0.001 wt % to 3 wt % of a metal complex, from 0.001 wt%, to 2 wt %, from 0.01 wt %, to 2 wt %, from 0.01 wt % to 1 wt %, orfrom 0.05 wt % to 0.5 wt % of a metal complex, where wt % is based onthe total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise:from 1 wt % to 10 wt % of a divinyl ether; from 45 wt % to 85 wt % of athiol-terminated polythioether; from 0.1 wt % to 5 wt % of an organicperoxide; and from 0.01 wt % to 2 wt % of a metal complex, where wt % isbased on the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise:from 4 wt % to 6 wt % of a divinyl ether; from 50 wt % to 80 wt % of athiol-terminated polythioether prepolymer; from 0.2 wt % to 4 wt % of anorganic peroxide; and from 0.02 wt % to 1 wt % of a metal complex, wherewt % is based on the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise:from 2 wt % to 8 wt % of a divinyl ether; from 60 wt % to 75 wt % of athiol-terminated polythioether prepolymer; from 0.5 wt % to 2 wt % of anorganic peroxide; and from 0.05 wt % to 0.5 wt % of a metal complex,where wt % is based on the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise:from 0.01 wt % to 2 wt % of a synergist such as a hydrogen donor such asa primary amine or a secondary amine; from 0.02 wt % to 1.5 wt %, from0.05 wt % to 1 wt %, or from 0.1 wt % to 0.5 wt %, where wt % is basedon the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise:from 1 wt % to 10 wt % of a polyalkenyl monomer; from 45 wt % to 85 wt %of a thiol-terminated prepolymer; from 0.1 wt % to 5 wt % of an organicperoxide; and from 0.001 wt % to 2 wt % of a metal complex, where wt %is based on the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise:from 4 wt % to 6 wt % of a polyalkenyl monomer; from 50 wt % to 80 wt %of a thiol-terminated prepolymer; from 0.2 wt % to 4 wt % of an organicperoxide; and from 0.002 wt % to 1 wt % of a metal complex, where wt %is based on the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise:from 2 wt % to 8 wt % of a polyalkenyl monomer; from 60 wt % to 75 wt %of a thiol-terminated prepolymer; from 0.5 wt % to 2 wt % of an organicperoxide; and from 0.005 wt % to 0.5 wt % of a metal complex, where wt %is based on the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise:from 1 wt % to 10 wt % of a polythiol monomer; from 45 wt % to 85 wt %of an alkenyl-terminated prepolymer; from 0.1 wt % to 5 wt % of anorganic peroxide; and from 0.001 wt % to 2 wt % of a metal complex,where wt % is based on the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise:from 4 wt % to 6 wt % of a polythiol monomer; from 50 wt % to 80 wt % ofan alkenyl-terminated prepolymer; from 0.2 wt % to 4 wt % of an organicperoxide; and from 0.002 wt % to 1 wt % of a metal complex, where wt %is based on the total weight of the curable composition.

Curable compositions provided by the present disclosure can comprise:from 2 wt % to 8 wt % of a polythiol monomer; from 60 wt % to 75 wt % ofan alkenyl-terminated prepolymer; from 0.5 wt % to 2 wt % of an organicperoxide; and from 0.005 wt % to 0.5 wt % of a metal complex, where wt %is based on the total weight of the curable composition.

Uncured sealants provided by the present disclosure can be provided as atwo-part system comprising a first part and a second part which can beprepared and stored separately, combined, and mixed at the time of use.

Curable sealant systems of the present disclosure can be provided astwo-part sealant compositions. The two-parts can be maintainedseparately and can be combined prior to use. A first part can comprise,for example, polyalkenyls, hydroxyl-functional vinyl ethers, inorganicfiller, organic filler, and lightweight filler. A second part cancomprise, for example, thiol-terminated sulfur-containing prepolymers,polythiols, organic filler, inorganic filler lightweight filler, andadhesion promoters. Optional additives can include plasticizers,pigments, solvents, reactive diluents, surfactants, thixotropic agents,fire retardants, and a combination of any of the foregoing. A metalcomplex can be added to the first part and an organic peroxide can beadded to the second part. A metal complex can be added to the secondpart and an organic peroxide can be added to the first part.

The first part and the second part can be formulated to be renderedcompatible when combined such that the constituents of the first andsecond parts can intermix and be homogeneously dispersed to provide asealant or coating composition for application to a substrate. Factorsaffecting the compatibility of the first and second parts include, forexample, viscosity, pH, density, and temperature.

A first part can comprise, for example, from 70 wt % to 90 wt %, from 72wt % to 88 wt %, or from 76 wt % to 84 wt %, of a polyalkenyl such as apoly(alkenyl) ether, where wt % is based on the total weight of thefirst part.

A first part can comprise, for example, from 70 wt % to 90 wt % of apolyalkenyl such as a poly(alkenyl) ether, from 3 wt % to 13 wt % of aplasticizer, and from 6 wt % to 16 wt % of a filler, where wt % is basedon the total weight of the first part. A first part can comprise, forexample, 72 wt % to 88 wt % of a poly(alkenyl) ether, from 5 wt % to 11wt % of a plasticizer, and from 8 wt % to 14 wt % of a filler, where wt% is based on the total weight of the first part. A first part cancomprise, for example, 76 wt % to 84 wt % of a poly(alkenyl) ether, from7 wt % to 9 wt % of a plasticizer, and from 10 wt % to 12 wt % of afiller, where wt % is based on the total weight of the first part.

A second part can comprise, for example, from 60 wt % to 80 wt %, from62 wt % to 78 wt %, or from 66 wt % to 74 wt %, of a thiol-terminatedsulfur-containing prepolymer, where wt % is based on the total weight ofthe second part.

A second part can comprise from 60 wt % to 80 wt % of a thiol-terminatedsulfur-containing prepolymer, from 5 wt % to 15 wt % of a filler, andfrom 11 wt % to 21 wt % of a silica gel, where wt % is based on thetotal weight of the second part. A second part can comprise from 62 wt %to 78 wt % of a thiol-terminated sulfur-containing prepolymer, from 7 wt% to 13 wt % of a filler, and from 13 wt % to 19 wt % of a silica gel,where wt % is based on the total weight of the second part. A secondpart can comprise from 66 wt % to 74 wt % of a thiol-terminatedsulfur-containing prepolymer, from 9 wt % to 11 wt % of a filler, andfrom 15 wt % to 17 wt % of a silica gel, where wt % is based on thetotal weight of the second part.

The pH of each of the parts of a sealant system can be selected toimprove the storage stability of each of the parts.

Curable compositions provided by the present disclosure can be used asaerospace sealants or coatings, and in particular, as sealants orcoatings where resistance to hydraulic fluid is desired. A sealantrefers to a curable composition that has the ability when cured toresist atmospheric conditions such as moisture and temperature and atleast partially block the transmission of materials such as water, watervapor, fuel, solvents, and/or liquids and gases.

Compositions provided by the present disclosure may be applied directlyonto the surface of a substrate or over an underlayer such as a primerby any suitable coating process.

Furthermore, methods are provided for sealing an aperture utilizing acomposition provided by the present disclosure. These methods comprise,for example, applying the curable composition to at least one surface ofa part; and curing the applied composition to provide a sealed part.

Compositions, including sealants, provided by the present disclosure maybe applied to any of a variety of substrates. Examples of substrates towhich a composition may be applied include metals such as titanium,stainless steel, steel alloy, aluminum, and aluminum alloy, any of whichmay be anodized, primed, organic-coated or chromate-coated; epoxy;urethane; graphite; fiberglass composite; Kevlar®; acrylics; andpolycarbonates. Compositions provided by the present disclosure may beapplied to a substrate such as aluminum and aluminum alloy.

Sealant compositions provided by the present disclosure may beformulated as Class A, Class B, or Class C sealants. A Class A sealantrefers to a brushable sealant having a viscosity of 1 poise to 500 poiseand is designed for brush application. A Class B sealant refers to anextrudable sealant having a viscosity from 4,500 poise to 20,000 poiseand is designed for application by extrusion via a pneumatic gun. AClass B sealant can be used to form fillets and sealing on verticalsurfaces or edges where low slump/slag is required. A Class C sealanthas a viscosity from 500 poise to 4,500 poise and is designed forapplication by a roller or combed tooth spreader. A Class C sealant canbe used for fay surface sealing. Viscosity can be measured according toSection 5.3 of SAE Aerospace Standard AS5127/1C published by SAEInternational Group.

Compositions provided by the present disclosure may be applied directlyonto the surface of a substrate or over an underlayer by any suitablecoating process known to those of ordinary skill in the art.

Furthermore, methods are provided for sealing an aperture utilizing acomposition provided by the present disclosure. These methods comprise,for example, providing the curable composition of the presentdisclosure; applying the curable composition to at least one surface ofa part; and curing the applied composition to provide a sealed part.

Compositions, including sealants, provided by the present disclosure maybe applied to any of a variety of substrates. Examples of substrates towhich a composition may be applied include metals such as titanium,stainless steel, steel alloy, aluminum, and aluminum alloy, any of whichmay be anodized, primed, organic-coated or chromate-coated; epoxy;urethane; graphite; fiberglass composite; Kevlar®; acrylics; andpolycarbonates. Compositions provided by the present disclosure may beapplied to a substrate such as aluminum and aluminum alloy.

A composition provided by the present disclosure may be cured underambient conditions, where ambient conditions refers to a temperaturefrom 20° C. to 25° C., and atmospheric humidity. A composition may becured under conditions encompassing a temperature from a 0° C. to 100°C. and humidity from 0% relative humidity to 100% relative humidity. Acomposition may be cured at a higher temperature such as at least 30°C., at least 40° C., or at least 50° C. A composition may be cured atroom temperature, e.g., 25° C. The methods may be used to seal apertureson aerospace vehicles including aircraft and aerospace vehicles.

Apertures, surfaces, joints, fillets, fay surfaces including apertures,surfaces, fillets, joints, and fay surfaces of aerospace vehicles,sealed with compositions provided by the present disclosure are alsodisclosed. The compositions and sealants can also be used to seatfasteners.

Curable compositions provided by the present disclosure can be to sealfasteners. Curable compositions provided by the present disclosure canbe use as seal caps. A seal cap refers to a sealant shaped to cover afastener. Thus, aspects of the invention include seal caps comprising acurable composition provided by the present disclosure. Seal caps andthiol/ene formulations suitable for use in seal caps are disclosed, forexample, in U.S. Pat. Nos. 9,533,798, 8,932,685, and 7,438,974, each ofwhich is incorporated by reference in its entirety. A seal cap can beprovided having cured or partially cured shell and filled with anuncured portion. The seal cap can be stored at low temperature until thetime of use. The uncured portion can be at least partially cured usingactinic radiation and/or can be cured without exposure to actinicradiation via the dark cure mechanism. As another example, a seal capcomprising a composition provided by the present disclosure can bedeposited onto a fastener and at least partially cured by exposure toactinic radiation with full cure developing over time via the dark curemechanism.

The time to form a viable seal using curable compositions of the presentdisclosure can depend on several factors as can be appreciated by thoseskilled in the art, and as defined by the requirements of applicablestandards and specifications. In general, curable compositions of thepresent disclosure develop adhesion strength within about 3 days toabout 7 days following mixing and application to a surface. In general,full adhesion strength as well as other properties of cured compositionsof the present disclosure becomes fully developed within 7 daysfollowing mixing and application of a curable composition to a surface.

A cured composition can have a thickness, for example, from 5 mils to 25mils (127 μm to 635 μm) such as from 10 mils to 20 mils (254 μm to 508μm).

The free radical photopolymerization reaction can be initiated byexposing a composition provided by the present disclosure to actinicradiation such as UV radiation, for example, for less than 120 seconds,less than 90 seconds, less than 60 seconds, or less than 30 seconds.

The free radical photopolymerization reaction can be initiated byexposing a composition provided by the present disclosure to actinicradiation such as UV radiation, for example, for from 15 seconds to 120seconds, from 15 seconds to 90 seconds, for rom 15 seconds to 60seconds.

The UV radiation can include irradiation at a wavelength at 394 nm.

The total power of the UV exposure can be, for example, from 50 mW/cm²to 500 mW/cm², from 50 mW/cm² to 400 mW/cm², from 50 mW/cm² to 300mW/cm², from 100 mW/cm² to 300 mW/cm², or from 150 mW/cm² to 250 mW/cm².

Curable compositions provided by the present disclosure can be exposedto a UV dose of 1 J/cm² to 4 J/cm² to cure the sealant. The UV source isa 8 W lamp with a UVA spectrum. Other doses and/or other UV sources canbe used. A UV dose for curing a sealant can be, for example, from 0.5J/cm² to 4 J/cm², from 0.5 J/cm² to 3 J/cm², from 1 J/cm² to 2 J/cm², orfrom 1 J/cm² to 1.5 J/cm².

Compositions provided by the present disclosure can also be cured withradiation at blue wavelength ranges such as from an LED.

Compositions provided by the present disclosure are curable withoutexposure to actinic radiation such as UV radiation. Composition can beat least partly curable upon exposure to actinic radiation and suchcompositions can include a photoionization. The actinic radiation suchas UV radiation can be applied to at least a portion of an appliedsealant. The sealant can be accessible to the actinic radiation and theportion of sealant exposed to the UV radiation can be a surface depth.For example, the actinic radiation can initiated the photopolymerizationreaction to a depth, for example, of at least 4 mm, at least 6 mm, atleast 8 mm, or at least 10 mm. A portion of the sealant may not beaccessible to actinic radiation either because of absorption orscattering of the actinic radiation of the sealant which prevents theactinic radiant from interacting with the full thickness of the sealant.A portion of the sealant may be obscured by the geometry of the partbeing sealed or may be obscured by an overlying structure.

Curable compositions provided by the present disclosure can be exposedto UV radiation to initiate the dual curing reactions. The compositionscan be exposed to a UV dose of, for example, from 1 J/cm² to 4 J/cm².The UV dose can be selected, for example, to provide a depth of UV curefrom 1 mm to 25 mm, from 2 mm to 20 mm, from 5 mm to 18 mm, or from 10mm to 15 mm. Any suitable UV wavelength can be used that initiates thegeneration of free radicals. For example, suitable UV wavelengths can bewithin a range, for example, from 365 nm to 395 nm.

The dark cure reaction can extend beyond the region exposed to theactinic radiation to a distance of, for example, 1 cm or less, 2 cm orless, 4 cm or less, 6 cm or less, 10 cm or less, or 20 cm or less. Forexample, the dark cure reaction can extend beyond the region exposed tothe actinic radiation to a distance from 0.1 cm to 20 cm, from 0.1 cm to10 cm, from 0.1 cm to 6 cm, from 0.1 cm to 4 cm, from 0.1 cm to 2 cm, orfrom 0.1 cm to 1 cm. The distance can refer to a depth within thecurable composition, a distance within the plane of a coating, or both.In other words, the distance can refer to a distance parallel and/ororthogonal to the direction of the actinic radiation.

Curable compositions provided by the present disclosure can be exposedto actinic radiation, for example, for 120 seconds or less, from 90seconds or less, for 60 seconds or less, for 30 seconds or less, or 15seconds or less. Curable compositions provided by the present disclosurecan be exposed to actinic radiation, for example, within a range from 10seconds to 120 seconds, from 15 seconds to 120 seconds, for 30 secondsto 90 seconds, or from 30 seconds to 60 seconds.

A curable composition can be applied to a surface. The curablecomposition can be exposed to actinic radiation. The actinic radiationcan extend to a depth in the thickness of the applied sealant, such as,for example, to a depth of 0.25 inches, 0.5 inches, 0.75 inches, 1 inch,1.25 inches or 1.5 inches. The portion of the sealant exposed to theactinic radiation can cure by a free radical mechanism. The depth ofactinic radiation exposure can depend on a number of factors including,for example, absorption by the materials forming the sealant, scatteringor radiation by materials forming the sealant such as by filler, and/orthe geometry of the applied sealant.

A portion of the applied composition may not be exposed to actinicradiation. For example, actinic radiation may not extend through thethickness of the applied sealant. The unexposed portion of the sealantunderlying the portion exposed to actinic radiation can cure via freeradicals generated by the organic peroxide/metal complex. Similarly,portions of the applied sealant adjacent the portion exposed to actinicradiation can cure by the organic peroxide/metal complex mechanism.

Curable compositions provided by the present disclosure, followingapplication to a part, can be exposed to actinic radiation for asufficient time to fully or partially cure the surface of the sealant.The full depth of the sealant can then cure with time via dark curemechanisms. Providing a fully or partially cured surface can facilitatehandling of the part.

Actinic radiation can be applied to a curable composition at any timeduring the curing process. For example, actinic radiation can be appliedto an applied sealant shortly after application or at any time while thesealant is curing. For example, it can be desirable to coat a largesurface area with a sealant an then expose the entire surface to actinicradiation. Actinic radiation can be applied once or several times duringthe curing process. In general exposing the sealant to actinic radiationwill cure the sealant to a certain depth. The depth of cure induced bythe actinic radiation can depend on a number of factors such as, forexample, the sealant formulation, the filler content and type, and theirradiation conditions. Actinic radiation can be applied to the sealantat any time during the cure.

Sealant compositions provided by the present disclosure can also cureupon exposure to room lighting.

Curable compositions provided by the present disclosure do not requireexposure to actinic radiation to cure. Cured compositions can cure underdark conditions via free radicals generated by the organicperoxide/metal complex mechanism. Cured compositions can cure attemperatures within a range from 20° C. to 30° C., such as from 22° C.to 28° C. Thus, the dark cure reaction does not require application ofheat or generation of free radicals in an area of the sealant adjacentthe dark cure area.

Cured compositions provided by the present disclosure, such as curedsealants, exhibit properties acceptable for use in aerospace sealantapplications. In general, it is desirable that sealants used in aviationand aerospace applications exhibit the following properties: peelstrength greater than 20 pounds per linear inch (pli) on AerospaceMaterial Specification (AMS) 3265B substrates determined under dryconditions, following immersion in JRF Type I for 7 days, and followingimmersion in a solution of 3% NaCl according to AMS 3265B testspecifications; tensile strength between 300 pounds per square inch(psi) and 400 psi; tear strength greater than 50 pounds per linear inch(pli); elongation between 250% and 300%; and hardness greater than 40Durometer A. These and other cured sealant properties appropriate foraviation and aerospace applications are disclosed in AMS 3265B, which isincorporated by reference in its entirety. It is also desirable that,when cured, compositions of the present disclosure used in aviation andaircraft applications exhibit a percent volume swell not greater than25% following immersion for one week at 60° C. (140° F.) at 760 torr(101 kPa) in Jet Reference Fluid (JRF) Type 1. Other properties, ranges,and/or thresholds may be appropriate for other sealant applications.

Cured compositions provided by the present disclosure can befuel-resistant. The term “fuel resistant” means that a composition, whenapplied to a substrate and cured, can provide a cured product, such as asealant, that exhibits a percent volume swell of not greater than 40%,in some cases not greater than 25%, in some cases not greater than 20%,and in other cases not more than 10%, after immersion for one week at140° F. (60° C.) and 760 torr (101 kPa) in JRF Type I according tomethods similar to those described in ASTM D792 (American Society forTesting and Materials) or AMS 3269 (Aerospace Material Specification).JRF Type I, as employed for determination of fuel resistance, has thefollowing composition: toluene: 28±1% by volume; cyclohexane(technical): 34±1% by volume; isooctane: 38±1% by volume; and tertiarydibutyl disulfide: 1±0.005% by volume (see AMS 2629, issued Jul. 1,1989, § 3.1.1., available from SAE (Society of Automotive Engineers)).

Compositions provided by the present disclosure provide a cured product,such as a sealant, exhibiting a tensile elongation of at least 200% anda tensile strength of at least 200 psi when measured in accordance withthe procedure described in AMS 3279, § 3.3.17.1, test procedureAS5127/1, § 7.7. In general, for a Class A sealant there is no tensileand elongation requirement. For a Class B sealant, as a generalrequirement, tensile strength is equal to or greater than 200 psi (1.38MPa) and elongation is equal to or greater than 200%. Acceptableelongation and tensile strength can be different depending on theapplication.

Compositions provide a cured product, such as a sealant, that exhibits alap shear strength of greater than 200 psi (1.38 MPa), such as at least220 psi (1.52 MPa), at least 250 psi (1.72 MPa), and, in some cases, atleast 400 psi (2.76 MPa), when measured according to the proceduredescribed in SAE AS5127/1 paragraph 7.8.

A cured sealant prepared from a composition provided by the presentdisclosure meets or exceeds the requirements for aerospace sealants asset forth in AMS 3277.

Curable compositions provided by the present disclosure can beformulated to exhibit a desired cure profile. A cure profile can becharacterized by an application time, a tack free time, a cure time, anda full cure time. Definitions of these durations are provided herein.For example, a curable composition provided by the present disclosurecan be formulated to exhibit an application time of 0.5 hours, a tackfree time of less than 2 hours, and a cure time of 3 hours at conditionsof 25° C. and 50% RH. Other formulations can exhibit, for example, anapplication time of 2 hours, a tack free time less than 8 hours, and acure time of 9 hours; or an application time of 4 hours, a tack freetime of less than 24 hours, and a cure time of less than 24 hours. Othercure profiles can be designed for a particular application and based onconsiderations such as volume of material, surface area, applicationmethod, thickness of coating, temperature, and humidity.

Depending on the application an acceptable extrusion rate can be atleast 15 g/min, at least 20 g/min, at least 30 g/min, at least 40 g/min,at least 50 g/min, or at least 60 g/min when extruded through a No. 404nozzle at a pressure of 90 psi (620 kPa).

For certain applications it can be desirable that the application timebe, for example, at least 2 hours, hat least 5 hours, at least 10 hours,at least 15 hours, at least 20 hours, or at least 25 hours.

The cure time is defined as the duration after the time when thecomponents of the sealant composition are first combined until the timewhen the surface hardness of the sealant is Shore 30A. Shore A hardnesscan be measured using Type A durometer according to ASTM D2240.

Sealants provided by the present disclosure are intended to be cured at25° C., however, the sealants can be cured at higher temperatures, whichwill decrease the tack free time and the cure time. Unless otherwiseclear from the context, the application, tack free time, and cure timerefer to the characteristic times of a curing profile for a sealantcured at 25° C.

After the cure time, the hardness of the sealant will continue toincrease until the sealant is fully cured. A fully cured sealant canhave a hardness, for example from Shore 40A to Shore 80A, from Shore 45Ato Shore 70A, or from Shore 50A to Shore 60A. Following curing to ahardness of Shore 30A, the sealant can fully curing within, for example,from 1 day to 6 weeks, from 3 days to 5 weeks, from 4 days to 4 weeks,or from 1 week to 3 weeks.

Short cure, dual cure sealants provided by the present disclosure can becharacterized, for example, of a tack free time of less than 1 day, lessthan 16 hours, or less than 8 hours. Short cure, dual cure sealantsprovided by the present disclosure can be characterized, for example, ofa tack free time from 2 hours to 24 hours, from 4 hours to 20 hours, orfrom 8 hours to 16 hours.

Long cure, dual cure sealants provided by the present disclosure can becharacterized, for example, of a tack free time of greater than 1 day,greater than 3 days, greater than 6 days or greater than 9 days. Longcure, dual cure sealants provided by the present disclosure can becharacterized, for example, of a tack free time from 1 day to 10 days,from 2 days to 8 days, or from 4 days to 6 days.

A long cure sealant can have, for example, an open time from 1 hour to 5hours and a cure time from 2 weeks to 4 weeks.

For example, using Mn(acac)₃ ad the metal complex, a sealant provided bythe present disclosure can exhibit an application time from 15 minutesto 2 hours, a tack free time from 14 hours to 3 days, and a cure timefrom 1 day to 3 days.

In general, the metal complex can provide a coarse control of a sealantcuring profile and an amine catalyst can provide a fine control of thesealant curing profile.

In general, for certain applications it can be desirable that theapplication time be from 15 minutes to 2 hours and the cure time be from3 hours to 36 hours. In general, for certain applications, it can bedesirable that the application time be long, and that the tack free timeand the cure time be short.

Compositions provided by the present disclosure can be cured usingradiation within the blue region of the electromagnetic spectrum. Forexample, compositions can be curable using radiation within a range, forexample, from 365 nm to 395 nm.

Apertures, surfaces, joints, fillets, fay surfaces including apertures,surfaces, fillets, joints, and fay surfaces of aerospace vehicles,sealed with compositions provided by the present disclosure are alsodisclosed. A composition provided by the present disclosure can be usedto seal a part. A part can include multiple surfaces and joints. A partcan include a portion of a larger part, assembly, or apparatus. Aportion of a part can be sealed with a composition provided by thepresent disclosure or the entire part can be sealed.

Compositions provided by the present disclosure can be used to sealparts exposed or potentially exposed to fluids such as solvents,hydraulic fluids, and/or fuel.

Compositions provided by the present disclosure can be used to seal apart including a surface of a vehicle.

The term “vehicle” is used in its broadest sense and includes all typesof aircraft, spacecraft, watercraft, and ground vehicles. For example, avehicle can include, aircraft such as airplanes including privateaircraft, and small, medium, or large commercial passenger, freight, andmilitary aircraft; helicopters, including private, commercial, andmilitary helicopters; aerospace vehicles including, rockets and otherspacecraft. A vehicle can include a ground vehicle such as, for example,trailers, cars, trucks, buses, vans, construction vehicles, golf carts,motorcycles, bicycles, trains, and railroad cars. A vehicle can alsoinclude watercraft such as, for example, ships, boats, and hovercraft.

A composition provided by the present disclosure can be used in a F/A-18jet or related aircraft such as the F/A-18E Super Hornet and F/A-18F(produced by McDonnell Douglas/Boeing and Northrop); in the Boeing 787Dreamliner, 737, 747, 717 passenger jet aircraft, an related aircraft(produced by Boeing Commercial Airplanes); in the V-22 Osprey; VH-92,S-92, and related aircraft (produced by NAVAIR and Sikorsky); in theG650, G600, G550, G500, G450, and related aircraft (produced byGulfstream); and in the A350, A320, A330, and related aircraft (producedby Airbus). Compositions provided by the present disclosure can be usedin any suitable commercial, military, or general aviation aircraft suchas, for example, those produced by Bombardier Inc. and/or BombardierAerospace such as the Canadair Regional Jet (CRJ) and related aircraft;produced by Lockheed Martin such as the F-22 Raptor, the F-35 Lightning,and related aircraft; produced by Northrop Grumman such as the B-2Spirit and related aircraft; produced by Pilatus Aircraft Ltd.; producedby Eclipse Aviation Corporation; or produced by Eclipse Aerospace(Kestrel Aircraft).

Compositions provided by the present disclosure can be used to sealparts and surfaces of vehicles such as fuel tank surfaces and othersurfaces exposed to or potentially exposed to aerospace solvents,aerospace hydraulic fluids, and aerospace fuels.

The present invention includes parts sealed with a composition providedby the present disclosure, and assemblies and apparatus comprising apart sealed with a composition provided by the present disclosure.

The present invention includes vehicles comprising a part such as asurface sealed with a composition provided by the present disclosure.For example, an aircraft comprising a fuel tank or portion of a fueltank sealed with a sealant provided by the present disclosure isincluded within the scope of the invention.

Compositions can be as coatings or sealants, and in particular sprayablecoatings and sealants having a high filler content such as, for example,a filler content from 1 wt % to 90 wt % and/or a filler content from 1vol % to 80 vol %. The coatings and sealants can be applied to anysuitable surface including for example, surfaces of vehicles,architectural surfaces, consumer products, electronic products, marineequipment, and industrial equipment.

Aspects of the Invention

Aspect 1. A composition comprising: a thiol-terminated sulfur-containingprepolymer; a polyalkenyl; a metal complex; and an organic peroxide.

Aspect 2. The composition of aspect 1, wherein the thiol-terminatedsulfur-containing prepolymer comprises a thiol-terminated polythioetherprepolymer, a thiol-terminated polysulfide prepolymer, athiol-terminated sulfur-containing polyformal prepolymer, athiol-terminated monosulfide prepolymer, or a combination of any of theforegoing.

Aspect 3. The composition of any one of aspects 1 to 2, wherein thethiol-terminated sulfur-containing prepolymer comprises athiol-terminated polythioether prepolymer.

Aspect 4. The composition of any one of aspects 1 to 3, wherein thethiol-terminated sulfur-containing prepolymer comprises athiol-terminated polythioether prepolymer of Formula (2a), athiol-terminated polythioether prepolymer of Formula (2b), or acombination thereof:

HS—R¹—[S—(CH₂)₂—O—(R²—O)_(m)(CH₂)₂—S—R¹—]_(n)SH  (2a)

{HS—R¹—[S—(CH₂)₂—O—(R²—O—)_(m)(CH₂)₂—S—R¹—]_(n)S-V′-}_(z)B  (2b)

-   -   wherein,        -   each R¹ independently comprises C₂₋₁₀ alkanediyl, C₆₋₈            cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, C₅₋₈            heterocycloalkanediyl, or —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—,            wherein,            -   p is an integer from 2 to 6;            -   q is an integer from 1 to 5;            -   r is an integer from 2 to 10;            -   each R³ independently comprises hydrogen or methyl; and            -   each X independently comprises O, S, or NR, wherein R                comprises hydrogen or methyl;        -   each R² is independently comprises C₁₋₁₀ alkanediyl, C₆₋₈            cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, or            —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, wherein p, q, r, R³, and X            are as defined as for R¹;        -   m is an integer from 0 to 50;        -   n is an integer from 1 to 60;        -   B represents a core of a z-valent, polyfunctionalizing agent            B(-V)_(z) wherein,            -   z is an integer from 3 to 6; and            -   each V is a moiety comprising a terminal group reactive                with a thiol; and        -   each -V′- is derived from the reaction of -V with a thiol.

Aspect 5. The composition of any one of aspects 1 to 4, wherein thepolyalkenyl comprises a bis(alkenyl) ether.

Aspect 6. The composition of any one of aspects 1 to 5, wherein thepolyalkenyl comprises cyclohexanedimethanol divinyl ether.

Aspect 7. The composition of any one of aspects 1 to 6, wherein themetal complex comprises cobalt(II)bis(2-ethyl hexanoate),manganese(III)(acetylacetonate)₃, iron(III)(acetylacetonate)₃, or acombination of any of the foregoing.

Aspect 8. The composition of any one of aspects 1 to 7, wherein theorganic peroxide comprises tert-butyl peroxybenzoate,

Aspect 9. The composition of any one of aspects 1 to 8, wherein themetal complex comprises a metal complex of Co(II), Co(III), Mn(II),Mn(III), Fe(II), Fe(III), Cu(II), or a combination of any of theforegoing.

Aspect 10. The composition of any one of aspects 1 to 9, furthercomprising a hydroxyl-functional vinyl ether.

Aspect 11. The composition of any one of aspects 1 to 10, furthercomprising 4-hydroxybutyl vinyl ether.

Aspect 12. The composition of any one of aspects 1 to 11, wherein thecomposition comprises from 55 wt % to 75 wt % of the thiol-terminatedsulfur-containing prepolymer, wherein wt % is based on the total weightof the composition.

Aspect 13. The composition of any one of aspects 1 to 12, wherein thecomposition comprises from 2 wt % to 10 wt % of the polyalkenyl, whereinwt % is based on the total weight of the composition.

Aspect 14. The composition of any one of aspects 1 to 13, wherein thecomposition comprises from 0.01 wt % to 3 wt % of the metal complex,wherein wt % is based on the total weight of the composition.

Aspect 15. The composition of any one of aspects 1 to 14, wherein thecomposition comprises from 0.2 wt % to 3 wt % of the organic peroxide,wherein wt % is based on the total weight of the composition.

Aspect 16. The composition of any one of aspects 1 to 15, wherein thecomposition comprises from 0.1 wt % to 2 wt % of a hydroxyl-functionalvinyl ether, wherein wt % is based on the total weight of thecomposition.

Aspect 17. The composition of any one of aspects 1 to 16, wherein thecomposition comprises: from 55 wt % to 75 wt % of the thiol-terminatedsulfur-containing prepolymer; from 2 wt % to 10 wt % of the polyalkenyl;from 0.01 wt % to 3 wt % of the metal complex; from 0.2 wt % to 3 wt %of the organic peroxide, from 0.1 wt % to 2 wt % of ahydroxyl-functional vinyl ether, wherein wt % is based on the totalweight of the composition.

Aspect 18. The composition of any one of aspects 1 to 17, wherein, thethiol-terminated sulfur-containing prepolymer comprises athiol-terminated polythioether prepolymer; the polyalkenyl comprisescyclohexanedimethanol divinyl ether; the metal complex comprisescobalt(II)bis(2-ethyl hexanoate), manganese(III)(acetylacetonate)₃,iron(III)(acetylacetonate)₃, or a combination of any of the foregoing;the organic peroxide comprises tert-butyl peroxybenzoate; and furthercomprising a hydroxyl-functional vinyl ether, a plasticizer, and apolythiol; wherein, the hydroxyl-functional vinyl ether comprises4-hydroxybutyl vinyl ether; the plasticizer comprises a polybutadiene;and the polythiol has thiol functionality of three, a thiolfunctionality of four, or a combination thereof.

Aspect 19. The composition of aspect 18, further comprising an organicfiller, an inorganic filler, a lightweight filler or a combination ofany of the foregoing.

Aspect 20. The composition of any one of aspects 1 to 19, wherein, themetal complex comprises a metal cation and an anion; the metal cationhas an oxidation number of 2, 3, or a combination thereof; and the anioncomprises an organic anion.

Aspect 21. The composition of aspect 20, wherein the metal cationcomprises a metal cation of Co, Mn, Fe, Cu, V, Cu, Al, or a combinationof any of the foregoing.

Aspect 22. The composition of any one of aspects 20 to 21, wherein theorganic anion comprises acetylacetonate.

Aspect 23. The composition of any one of aspects 1 to 22, wherein thecomposition further comprises a polythiol, a photoinitiator, aplasticizer, a silica gel, a filler, or a combination of any of theforegoing.

Aspect 24. The composition of any one of aspects 1 to 23, wherein thecomposition further comprises from 0.1 wt % to 3 wt % of a plasticizer,wherein wt % is based on the total weight of the composition.

Aspect 25. The composition of any one of aspects 1 to 24, wherein thecomposition further comprises from 15 wt % to 25 wt % of a filler,wherein wt % is based on the total weight of the composition.

Aspect 26. The composition of any one of aspects 1 to 25, wherein thecomposition further comprises a filler, wherein the filler comprises anorganic filler, fumed silica, silica gel, a lightweight filler, or acombination of any of the foregoing.

Aspect 27. The composition of any one of aspects 1 to 26, wherein thecomposition comprises from 10 wt % to 20 wt % of silica gel, wherein wt% is based on the total weight of the composition.

Aspect 28. The composition of any one of aspects 1 to 27, wherein thecomposition comprises from 5 wt % to 15 wt % silica gel, wherein wt % isbased on the total weight of the composition.

Aspect 29. The composition of any one of aspects 1 to 28, wherein thecomposition is curable under dark conditions.

Aspect 30. The composition of any one of aspects 1 to 29, wherein thecomposition has an application time equal to or greater than 30 minutes.

Aspect 31. The composition of any one of aspects 1 to 30, wherein thecomposition fully cures under dark conditions within twelve (12) days.

Aspect 32. A cured sealant comprising the composition of any one ofaspects 1 to 31.

Aspect 33. The cured sealant of aspect 32, wherein the cured sealantexhibits a tensile strength greater than 200 psi (1.3 MPa) and anelongation greater than 200% following exposure to Jet Reference FluidType I according to AMS 3269, where tensile strength and elongation aredetermined according to AMS 3279.

Aspect 34. A part sealed with the cured sealant of any one of aspects 32to 33.

Aspect 35. A method of sealing a part comprising: applying thecomposition of any one of aspects 1 to 31 to a part; and allowing theapplied composition to cure, to seal the part.

Aspect 36. The method of aspect 35, further comprising, after applyingthe composition, exposing at least a portion of the applied compositionto actinic radiation.

Aspect 37. A sealant system, comprising: a first part, wherein the firstpart comprises a polyalkenyl; and a second part, wherein the second partcomprises a thiol-terminated sulfur-containing prepolymer, wherein thefirst part, the second, or both the first and second parts comprise ametal complex and an organic peroxide.

Aspect 38. The sealant system of aspect 37, wherein the first part, thesecond, or both the first and second parts comprise a UV-sensitivephotoinitiator.

Aspect 39. A sealant comprising the sealant system of any one of aspects37 to 38, wherein the first part and the second part are combined.

Aspect 40. A part sealed with the sealant system of any one of aspects37 to 39.

Aspect 41. A method of sealant a part, comprising combining the firstpart and the second part of the sealant system of any one of aspects 37to 40 to provide a sealant; applying the sealant to a part; and allowingthe applied sealant to cure, to seal the part.

Aspect 42. The method of aspect 41, further comprising, after applyingthe sealant, exposing at least a portion of the applied sealant toactinic radiation.

Aspect 1A. A composition comprising: a polythiol, wherein the polythiolcomprises a thiol-terminated prepolymer; a polyalkenyl, wherein thepolyalkenyl comprises an alkenyl-terminated prepolymer, a polyalkenylmonomer, or a combination thereof; a metal complex; and an organicperoxide.

Aspect 1Aa. The composition of aspect 1A, wherein the polythiolcomprises a thiol-terminated prepolymer.

Aspect 2A. The composition of aspect 1A, wherein the thiol-terminatedprepolymer comprises a thiol-terminated sulfur-containing prepolymer.

Aspect 3A. The composition of aspect 2A, wherein the thiol-terminatedsulfur-containing prepolymer comprises a thiol-terminated polythioetherprepolymer, a thiol-terminated polysulfide prepolymer, athiol-terminated sulfur-containing polyformal prepolymer, athiol-terminated monosulfide prepolymer, or a combination of any of theforegoing.

Aspect 4A. The composition of aspect 3A, wherein the thiol-terminatedsulfur-containing prepolymer comprises a thiol-terminated polythioetherprepolymer.

Aspect 5A. The composition of aspect 4A, wherein the thiol-terminatedsulfur-containing prepolymer comprises a moiety having the structure ofFormula (2c):

—S—R¹—[S-A-S—R¹—]_(n)—S—  (2c)

-   -   wherein,        -   n is an integer from 1 to 60;        -   each R¹ is independently selected from C₂₋₁₀ alkanediyl,            C₆₋₈ cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, C₅₋₈            heterocycloalkanediyl, and —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—,            wherein,            -   p is an integer from 2 to 6;            -   q is an integer from 1 to 5;            -   r is an integer from 2 to 10;            -   each R³ is independently selected from hydrogen and                methyl; and            -   each X is independently selected from O, S, and NR,                wherein R is selected from hydrogen and methyl; and        -   each A is independently a moiety derived from a polyvinyl            ether of Formula (3) and a polyalkenyl polyfunctionalizing            agent of Formula (4):

CH₂═CH—O—(R²—O)_(m)—CH═CH₂  (3)

B(—R⁷⁰—CH═CH₂)_(z)  (4)

-   -   -   wherein,            -   m is an integer from 0 to 50;            -   each R² is independently selected from C₁₋₁₀ alkanediyl,                C₆₋₈ cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, and                —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, wherein p, q, r, R³,                and X are as defined as for R¹;            -   B represents a core of a z-valent, polyalkenyl                polyfunctionalizing agent B(-R⁷⁰—CH═CH₂)_(z) wherein,            -   z is an integer from 3 to 6; and            -   each R⁷⁰ is independently selected from C₁₋₁₀                alkanediyl, C₁₋₁₀ heteroalkanediyl, substituted C₁₋₁₀                alkanediyl, and substituted C₁₋₁₀ heteroalkanediyl.

Aspect 6A. The composition of aspect 4A, wherein the thiol-terminatedsulfur-containing polythioether comprises a thiol-terminatedpolythioether prepolymer of Formula (2a), a thiol-terminatedpolythioether prepolymer of Formula (2b), or a combination thereof:

HS—R¹—[S—(CH₂)₂—O—(R²—O)_(m)(CH₂)₂—S—R¹—]_(n)SH  (2a)

{HS—R—[S—(CH₂)₂—O—(R²—O—)_(m)(CH₂)₂—S—R¹—]_(n)S-V′-}_(z)B  (2b)

-   -   wherein,        -   each R¹ independently comprises C₂₋₁₀ alkanediyl, C₆₋₈            cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, C₅₋₈            heterocycloalkanediyl, or —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—,            wherein,        -   p is an integer from 2 to 6;        -   q is an integer from 1 to 5;        -   r is an integer from 2 to 10;        -   each R³ independently comprises hydrogen or methyl; and        -   each X independently comprises O, S, or NR, wherein R            comprises hydrogen or methyl;        -   each R² is independently comprises C₂₋₁₀ alkanediyl, C₆₋₈            cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, or            —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, wherein p, q, r, R³, and X            are as defined as for R¹;        -   m is an integer from 0 to 50;        -   n is an integer from 1 to 60;        -   B represents a core of a z-valent, polyfunctionalizing agent            B(-V)_(z) wherein,            -   z is an integer from 3 to 6; and            -   each V is a moiety comprising a terminal group reactive                with a thiol; and            -   each -V′- is derived from the reaction of -V with a                thiol.

Aspect 7A. The composition of any one of aspects 1A to 6A, wherein thealkenyl-terminated prepolymer comprises an alkenyl-terminatedsulfur-containing prepolymer.

Aspect 7Aa. The composition of any one of aspects 1A to 67A, wherein thepolythiol comprises a polythiol monomer.

Aspect 8A. The composition of aspect 7Aa, wherein the polythiol monomercomprises a dithiol monomer, a polythiol monomer having a thiolfunctionality greater than two, or a combination thereof.

Aspect 9A. The composition of any one of aspects 7A to 8A, wherein thepolythiol monomer comprises a sulfur-containing dithiol monomer, asulfur-containing polythiol monomer having a thiol functionality greaterthan two, or a combination thereof.

Aspect 10A. The composition of any one of aspects 1A to 9A, wherein thepolyalkenyl monomer comprises a dialkenyl monomer, a polyalkenyl monomerhaving an alkenyl functionality greater than two, or a combinationthereof.

Aspect 11A. The composition of any one of aspects 1A to 10A, wherein thepolyalkenyl monomer comprises a sulfur-containing dialkenyl monomer, asulfur-containing polyalkenyl monomer having a alkenyl functionalitygreater than two, or a combination thereof.

Aspect 12A. The composition of any one of aspects 1A to 11A, wherein thepolyalkenyl monomer comprises a bis(alkenyl) ether.

Aspect 13A. The composition of any one of aspects 1A to 12A, wherein thepolythiol comprises a thiol-terminated polythioether prepolymer; and thepolyalkenyl comprises a bis(alkenyl) ether.

Aspect 14A. The composition of any one of aspects 1A to 13A, wherein thepolyalkenyl monomer comprises ethylene glycol divinyl ether (EG-DVE),butanediol divinyl ether (BD-DVE), hexanediol divinyl ether (HD-DVE),diethylene glycol divinyl ether (DEG-DVE), triethylene glycol divinylether (TEG-DVE), tetraethylene glycol divinyl ether,cyclohexanedimethanol divinyl ether, or a combination of any of theforegoing.

Aspect 15A. The composition of any one of aspects 1A to 14A, wherein themetal complex comprises cobalt(II)bis(2-ethyl hexanoate),manganese(III)(acetylacetonate)₃, iron(III)(acetylacetonate)₃, or acombination of any of the foregoing.

Aspect 16A. The composition of any one of aspects 1A to 15A, wherein theorganic peroxide comprises tert-butyl peroxybenzoate.

Aspect 17A. The composition of any one of aspects 1A to 16A, wherein themetal complex comprises a metal complex of Co(II), Co(III), Mn(II),Mn(III), Fe(II), Fe(III), Cu(II), V(III), or a combination of any of theforegoing.

Aspect 17Aa. The composition of any one of aspects 1A to 17A, whereinthe metal complex comprises an organic ligand, wherein the organicligand is acetylacetonate.

Aspect 18A. The composition of any one of aspects 1A to 17Aa, furthercomprising a hydroxyl-functional vinyl ether.

Aspect 19A. The composition of aspect 18A, comprising 4-hydroxybutylvinyl ether.

Aspect 20A. The composition of any one of aspects 1A to 19A, wherein thecurable composition comprises a free radical photoinitiator.

Aspect 21A. The composition of any one of aspects 1A to 20A, wherein thecurable composition comprises a hydrogen donor.

Aspect 22A. The composition of aspect 21A, wherein the hydrogen donorcomprises a primary amine, a secondary amine or a combination thereof.

Aspect 23A. The composition of any one of aspects 21A to 22A, whereinthe composition comprises from 45 wt % to 85 wt % of thethiol-terminated sulfur-containing prepolymer, wherein wt % is based onthe total weight of the composition.

Aspect 24A. The composition of any one of aspects 1A to 23A, wherein thecomposition comprises from 1 wt % to 10 wt % of the polyalkenyl, whereinwt % is based on the total weight of the composition.

Aspect 25A. The composition of any one of aspects 1A to 24A, wherein thecomposition comprises from 0.001 wt % to 2 wt % of the metal complex,wherein wt % is based on the total weight of the composition.

Aspect 26A. The composition of any one of aspects 1A to 25A, wherein thecomposition comprises from 0.1 wt % to 5 wt % of the organic peroxide,wherein wt % is based on the total weight of the composition.

Aspect 27A. The composition of any one of aspects 1A to 26A, wherein thecomposition further comprises from 0.01 wt % to 3 wt % of ahydroxyl-functional vinyl ether, wherein wt % is based on the totalweight of the composition.

Aspect 28A. The composition of any one of aspects 1A to 27A, wherein thecomposition further comprises from 0.01 wt % to 2 wt % of aphotoinitiator, wherein wt % is based on the total weight of thecomposition.

Aspect 29A. The composition of any one of aspects 1A to 28A, wherein thecomposition further comprises from 0.01 wt % to 2 wt % of a primaryamine, a secondary amine, a tertiary amine, or a combination thereof,wherein wt % is based on the total weight of the composition.

Aspect 30A. The composition of any one of aspects 1A to 29A, wherein thecomposition comprises from 45 wt % to 85 wt % of the thiol-terminatedsulfur-containing prepolymer; from 1 wt % to 10 wt % of the polyalkenyl;from 0.01 wt % to 2 wt % of the metal complex; and from 0.1 wt % to 5 wt% of the organic peroxide, wherein wt % is based on the total weight ofthe composition.

Aspect 31A. The composition of any one of aspects 1A to 30A, wherein,the thiol-terminated sulfur-containing prepolymer comprises athiol-terminated polythioether prepolymer; the polyalkenyl comprisescyclohexanedimethanol divinyl ether, triethylene glycol divinyl ether ora combination thereof; the metal complex comprises cobalt(II)bis(2-ethylhexanoate), manganese(III)(acetylacetonate)₃,iron(III)(acetylacetonate)₃, or a combination of any of the foregoing;the organic peroxide comprises tert-butyl peroxybenzoate; and furthercomprising a hydroxyl-functional vinyl ether, a photoinitiator, and apolythiol; wherein, the hydroxyl-functional vinyl ether comprises4-hydroxybutyl vinyl ether; and the polythiol has thiol functionality ofthree, a thiol functionality of four, or a combination thereof.

Aspect 32A. The composition of aspect 31A, further comprising an organicfiller, an inorganic filler, a lightweight filler, or a combination ofany of the foregoing.

Aspect 33A. The composition of any one of aspects 1A to 32A, wherein,the metal complex comprises a metal cation and an anion; the metalcation has an oxidation number of 2, 3, or a combination thereof; andthe anion comprises an organic anion.

Aspect 34A. The composition of aspect 33A, wherein the metal cationcomprises a metal cation of Co, Mn, Fe, Cu, V, Cu, Al, or a combinationof any of the foregoing.

Aspect 35A. The composition of any one of aspects 33A to 34A, whereinthe organic anion comprises acetylacetonate.

Aspect 36A. The composition of any one of aspects 1A to 35A, wherein thecomposition further comprises a polythiol, a photoinitiator, aplasticizer, a silica gel, a filler, or a combination of any of theforegoing.

Aspect 37A. The composition of any one of aspects 1 to 36A, wherein thecomposition further comprises from 0.01 wt % to 4 wt % of theplasticizer, wherein wt % is based on the total weight of thecomposition.

Aspect 38A. The composition of any one of aspects 36A to 37A, whereinthe composition comprises from 1 wt % to 50 wt % of the filler, whereinwt % is based on the total weight of the composition.

Aspect 39A. The composition of any one of aspects 36A to 38A, whereinthe filler comprises an organic filler, fumed silica, silica gel, alightweight filler, or a combination of any of the foregoing.

Aspect 40A. The composition of any one of aspects 36A to 39A, whereinthe composition comprises from 10 wt % to 20 wt % of the silica gel,wherein wt % is based on the total weight of the composition.

Aspect 41A. The composition of any one of aspects 36A to 39A, whereinthe composition comprises from 5 wt % to 15 wt % the silica gel, whereinwt % is based on the total weight of the composition.

Aspect 42A. The composition of any one of aspects 1A to 41A, wherein thecomposition is curable under dark conditions.

Aspect 43A. The composition of any one of aspects 1A to 42A, wherein thecomposition has an application time equal to or greater than 30 minutes.

Aspect 44A. The composition of any one of aspects 1A to 43A, wherein thecomposition fully cures to a hardness of Shore 30A under dark conditionswithin 4 weeks.

Aspect 45A. The composition of any one of aspects 1A to 44A, wherein,the composition is both curable upon exposure to actinic radiation; andthe composition is curable without exposure to actinic radiation.

Aspect 46A. The composition of any one of aspects 1A to 45A, wherein thecomposition is curable at a temperature from 20° C. to 30° C.

Aspect 47A. The composition of any one of aspects 1A to 46A, wherein thecomposition is curable upon exposure to a 1 J/cm² to 4 J/cm² from a UVAsource.

Aspect 48A. The composition of any one of aspects 1A to 47A, wherein thecomposition is curable under dark conditions at a temperature of 25° C.

Aspect 49A. A cured sealant prepared from the composition of any one ofaspects 1A to 48A.

Aspect 50A. The cured sealant of aspect 49A, wherein the cured sealantexhibits a tensile strength greater than 200 psi (1.3 MPa) and anelongation greater than 200% following exposure to Jet Reference FluidType I according to AMS 3269, where tensile strength and elongation aredetermined according to AMS 3279.

Aspect 51A. A part sealed with the cured sealant of any one of aspects49A to 50A.

Aspect 52A. A vehicle comprising the cured sealant of any one of aspects49A to 50A.

Aspect 53A. An aerospace vehicle comprising the cured sealant of any oneof aspects 49A to 50A.

Aspect 54A. A method of sealing a part comprising: applying thecomposition of any one of aspects 1A to 48A to a part; and allowing theapplied composition to cure, to seal the part.

Aspect 55A. The method of aspect 54A, further comprising, after applyingthe composition, exposing at least a portion of the applied compositionto actinic radiation.

Aspect 56A. A sealant system, comprising: a first part, wherein thefirst part comprises a polyalkenyl; and a second part, wherein thesecond part comprises a polythiol; wherein the first part comprises ametal complex and the second part comprises an organic peroxide; orwherein the first part comprises an organic peroxide and the second partcomprises a metal complex.

Aspect 56Aa. The sealant system of aspect 56A, wherein the polyalkenyl,the polythiol, the metal complex, and the organic peroxide are definedas in any of aspects 1A to 19A, 31A, and 33A to 35A.

Aspect 56Ab. The sealant system of any one of aspects 56A or 56Aa,wherein the sealant system comprises any one of aspects 21A, 22A, 32A,36A to 48A, or a combination of any of the foregoing.

Aspect 57A. The sealant system of aspect 56A, wherein the first part,the second, or both the first and second parts comprise a UV-sensitivephotoinitiator.

Aspect 58A. A sealant prepared from the sealant system of aspect 56A,wherein the first part and the second part are combined.

Aspect 59A. A part sealed with the sealant system of aspect 56A.

Aspect 60A. A vehicle comprising the cured sealant of aspect 56A.

Aspect 61A. An aerospace vehicle comprising the cured sealant of aspect56A.

Aspect 62A. A method of sealing a part, comprising: combining the firstpart and the second part of the sealant system of aspect 56A to providea sealant; applying the sealant to a part; and allowing the appliedsealant to cure, to seal the part.

Aspect 63A. The method of aspect 62A, further comprising, after applyingthe sealant, exposing at least a portion of the applied sealant toactinic radiation.

Aspect 64A. A seal cap comprising the cured sealant of aspect 56A.

Aspect 65A. A method of sealing a fastener comprising applying acomposition of any one of aspects 1A to 48A to a fastener and curing theapplied composition.

EXAMPLES

Embodiments provided by the present disclosure are further illustratedby reference to the following examples, which describe the compositionsprovided by the present disclosure and uses of such compositions. Itwill be apparent to those skilled in the art that many modifications,both to materials, and methods, may be practiced without departing fromthe scope of the disclosure.

Example 1 UV Curable-Unmodified Composition

A curable composition was prepared by combining Part A and Part B.

The constituents of Part A and Part B are provided in Table 1 and Table2, respectively.

Preparation of Part A: In a Black Max 200 JAR (Flack Tek Inc.; Landrum,S.C.) cup, the Part A composition was prepared by sequentially addingvinyl ethers, initiators, plasticizers, and fillers (Table 1) followedby gentle mixing first using a spatula and then by using a Speed Mixer(Hauschild, Model No. DAC 600FVZ) at 2,000 rpm for 30 s. After addingthe fumed silica, the resulting mixture was mixed at 2,000 rpm for 60 sto produce a well-dispersed mixture having a viscosity of ca. 280 poise(28 Pa-s) (Brookfield Viscometer CAP 2000; Spindle #7, 10 rpm, 25° C.).In addition, before adding Part A to a formulation, the cup was mixed at2,000 rpm for 30 s to ensure homogeneity before transferring thematerial to a formulating cup.

Preparation of Part B: In a Hauschild Max 200 JAR, 57.34 g of Permapol®P-3.1 E prepolymer (PPG Aerospace, Sylmar, Calif.) (Thiol EW: 1625) wasadded followed by 13.53 g of a higher functionality Permapol® P3.1 E-2.8(PPG Aerospace, Sylmar, Calif.) (Thiol EW: 1531) and 2.49 g of apolythiol (Table 2). The resulting mixture was first hand-mixed using aspatula followed by mixing at 1,200 rpm for 1 min using a HauschildSpeed Mixer. To this mixture, 5.39 g of Acumist® A6, a micronizedoxidized polyethylene homopolymer (Honeywell International, MorrisPlains, N.J.) was added, followed by Hauschild mixing at 2,000 rpm for 1min. To this mixture, fumed silicas were added followed by mixing at2,350 rpm for 2 min. This was followed by the addition of 16.37 g ofsilica gel (Gasil® IJ35, PQ Corporation, Valley Forge, Pa.) and mixingat 2,300 rpm for 2 min (twice) with an intermittent hand mixing toensure all filler in the cup had been incorporated. This was followed bythe addition of lightweight filler (Expancel® 920; AkzoNobel Inc.) andmixing at 1800 rpm for 1 min. This was followed by the addition ofadhesion promoter (mercaptopropyl trimethoxy silane) and mixed at 2,000rpm for 1 min (twice) with an intermittent hand mix. The finalformulation had a viscosity of ca. 20,000 poise (2,000 Pa-s) (BrookfieldViscometer CAP2000; Spindle #7, 10 rpm 25° C.).

TABLE 1 Composition of UV Curable Components: Part A. Amount ComponentProduct wt % Divinyl ether Cyclohexanedimethanol 69.41 divinyl etherHydroxyl-functional 4-hydroxybutyl vinyl ether 9.49 vinyl etherPhotoinitiator Darocure ® TPO 0.31 Lucirin ® TPO Speedcure TPOPhotoinitiator Irgacure ® TPO 1.25 Omnirad ® 551 PlasticizerPolybutadiene 8.45 Inorganic filler Precipitated calcium carbonate 0.91Inorganic filler Fumed silica 10.18

TABLE 2 Composition of UV Curable Components: Part B. Amount ComponentProduct wt % Thiol-terminated Permapol ® 3.1E 57.34 polythioether (thiolEW 1625) Thiol-terminated Permapol ® 3.1E−2.8 13.53 polythioether (thiolEW 1531) Polythiol — 2.49 Micronized oxidized Acumist ® A6 5.39polyethylene homopolymer Inorganic filler Fumed Silica 1.94 Inorganicfiller Fumed Silica 2.56 Silica gel Gasil ® IJ35 16.37 LightweightFiller Expancel ® 920 DE 40 D30 0.25 Adhesion Promoter Mercaptopropyltrimethoxy 0.13 silane

Part A and Part B were mixed in a weight ratio of 100 g Part B to 8 gPart A to provide UV-curable compositions. The basic UV-curablecomposition was modified to impart dual-cure capabilities as disclosedin the following examples.

Example 2 Dual Cure Formulation

In a Black 200 JAR Hauschild cup, 46.3 g of Part A was combined with 3.7g of Part B (100:8 weight ratio). The mixture was mixed at 2,000 rpm for1 min after hand mixing with a spatula. To this mixture, using adropper, 0.945 g of Trigonox® C (AkzoNobel Polymer Chemicals LLC;tert-butyl peroxybenzoate) was added dropwise. (Note: Organic peroxidesare highly reactive species and all safety, handling and storageinstructions from the manufacturer must be strictly adhered to). Theresulting mixture was carefully hand mixed with a stainless steelspatula followed by Hauschild mixing at 1,600 rpm for 30 s. Care shouldbe taken not to generate too much heat by excessive mixing (longer timeor higher spin rate) to avoid reducing the peroxide activity throughpremature decomposition.

To prepare the Fe(III)(acac)₃ solution, separately, in a 20 mL glassvial a 10 wt % solution of Fe(III)(acetylacetonate)₃ was made inacetylacetone. The resulting solution was deeply colored. Both chemicalsare commercially available from Sigma-Aldrich (St. Louis, Mo.).

To make the final composition of Example 2, 0.07 g of the Fe(III)(acac)₃solution was added to the mixture of Part A, Part B, and Trigonox® C.The resulting sample was hand mixed, followed by Hauschild mixing at1,800 rpm for 30 s. The resulting composition was poured into a small⅜-inch deep (1.9 inch diameter) aluminum cup for hardness measurements.A flow-out sample was also made for testing tensile and elongation bypouring 20 g to 30 g of the composition between two polyethylene sheetsseparated by 0.125-inch thick spacers and pressing the layers betweentwo steel plates to create a disc-shaped sample to be further cured. Theresulting samples were (a) immediately UV cured; or (b) kept in a dark(light free) closet, to generate light cure (a) and dark cure (b)samples, respectively, for further testing.

For hardness testing the thickness of the test samples was 0.25 inchesand the sealant thickness for the flow-out samples was 0.125-inches.

Example 3 Dual Cure Formulation

In a black 200 JAR Hauschild cup, 46.3 g of Part A, 3.7 g of Part B, and0.945 g of Trigonox® C were mixed sequentially and prepared as describedin Example 2.

To prepare the Mn(III)(acetylacetonate)₃ solution, in a 20 mL glass viala 10% solution of Mn(III)(acetylacetonate)₃ was made by combining 90parts toluene and 10 parts acetylacetonate andMn(III)(acetylacetonate)₃. The resulting solution was deeply colored.All reagents used are commercially available from Sigma-Aldrich (St.Louis, Mo.).

To make a curable composition of Example 3 0.5 g of theMn(III(acetylacetonate)₃ solution was added to the mixture of Part A,Part B, and Trigonox® C, followed by hand mixing and Hauschild mixing at1,800 rpm for 30 s. Hardness and flow-out samples for both light anddark cure were prepared using the methods described in Example 2.

Example 4 Dual Cure Formulation

In a black 200 JAR Hauschild cup, 46.3 g of Part A and 3.7 g of Part Bwere mixed and prepared as described in Example 2. To this mixture, 0.47g of a 50/50 solution of Trigonox® C in Jayflex™ DINP Plasticizer (Careshould be taken in diluting and handling organic peroxides!) was addeddropwise followed by hand mixing using a stainless steel spatula. Themixture was further mixed in a Hauschild Mixer at 1,600 rpm for 30 s. Tothis mixture 0.23 g of Duroct® Cobalt 12% (Dura Chemicals; Emeryville,Calif.) was added, followed by hand mixing and Hauschild mixing at 1,800rpm for 30 s to prepare the final sealant composition. Hardness and flowout samples for both light and dark cure were prepared according to themethods described in Example 2.

To prepare the cobalt catalysts, Duroct® Cobalt 12% was used as acommercially available source for cobalt(II)bis(2-ethylhexanoate) and isprovided as an 80% solution (w/w) in Stoddard Solvent and2-ethylhexanoic acid.

To understand the cure characteristics and transparency (at 395 nm) ofcured compositions when modified with catalysts for dark/dual cure,depth of cure measurements were performed. These measurements were doneby applying the sealant formulations in a groove of a 0.4-inch(length×width is 0.5 in×0.5 in) sample. The sample was exposed for 30 sat a flux of 224 mW/cm² at 395 nm. The depth of cure was obtained bydetermining the depth at which the sample was fully cured by theexposure. Flow-out and peel samples were exposed to a dose for 60 s at aflux of 224 mW/cm² at 395 nm.

The properties of the samples were tested under various conditions:unmodified, modified (UV Cure) and modified (Dark Cured) referred toExamples 2-4 are summarized in Tables 3A-3C.

TABLE 3A Dual cure modifications to UV-curable compositions for thesealant of Example 2. Dual Cure Modifications UV Curable MetalComposition Trigonox ® Metal Metal Activator Component Part A Part B CType Activator Composition Amount, g 46.3 3.7 0.945 Fe(III)(acac)₃ 0.0710 wt % in acetyl acetonate Note A + B is 50 g. Actual Actual All otherperoxide 0.014% concentrations wt % 1.89 were calculated based on thisweight

TABLE 3B Dual cure modifications to UV-curable compositions for thesealant of Example 3. Dual Cure Modifications UV Curable Metal MetalComposition Trigonox ® Activator Metal Activator Component Part A Part BC Type Activator Composition Amount, g 46.3 3.7 0.945 Mn(III)(acac)₃ 0.710 wt % in a 90/10 solution of acetylacetonate (1)) and toluene (90)Note A + B is 50 g. Actual Actual All other peroxide 0.10%concentrations wt % were 1.89 calculated based on this weight

TABLE 3C Dual cure modifications to UV-curable compositions for thesealant of Example 4. Dual Cure Modifications UV Curable Metal MetalComposition Trigonox ® Activator Metal Activator Component Part A Part BC Type Activator Composition Amount g 46.3 3.7 0.47 g ofCobalt(II)bis(2- 0.25 80 wt % in 50/50 ehtylhexanoate) Stoddard solutionSolvent and of 2- Trigonox ® ethylhexanoic C in acid Jayflex ® DINPPlasticizer Note A + B is 50 g. Actual Actual All other peroxide 0.37%concentrations wt % 0.47 were calculated based on this weight

Peel strength tests were performed on AMS 27725 panels using standard180° peel preparation methods. The substrate after typical surfacepreparation was primed with a silane-based primer.

The results are presented in Tables 4-7.

TABLE 4 UV-cured properties of the composition of Example 1 with nomodifications. UV Cured, 1 day Dark Cure, 6 day Tensile strength, psi433 ± 33 n/a Elongation, % 312 ± 22 n/a Depth of Cure ⅜-inch n/a Shore A48-50 n/a Peel Adhesion (UV only) 30 lb/in, 100% n/a cohesive

TABLE 5 Cured properties of the modified sealant of Example 4. UV Cured,1 day Dark Cure, 6 day Tensile strength, psi 272 ± 39 272 ± 30Elongation, % 499 ± 54 504 ± 86 Depth of Cure (UV only) ⅛-inch n/a ShoreA 40-44 38-40 Peel Adhesion 25 lb/in, 100% 23 lb/in, 100% cohesivecohesive

TABLE 6 Cured properties of the modified sealant of Example 3. UV Cured,1 day Dark Cure, 3 day Tensile strength, psi 445 ± 18 455 ± 58Elongation, % 308 ± 6  302 ± 47 Depth of Cure (UV only) ⅕-inch n/a ShoreA 43 44 Peel Adhesion (Dark only) n/a 30 lb/in, 100% cohesive

TABLE 7 Cured properties of the modified sealant of Example 2. UV Cured,1 day Dark Cure, 14 day Tensile strength, psi 414 ± 20 408 ± 24Elongation, % 286 ± 27 351 ± 20 Depth of Cure (UV only) 2/11 inch n/aHardness, Shore A 44 43 Peel Adhesion (UV only) n/a —

Peel strength was determined according to AS 5127/1C. Peel results showfavorable failure modes (100% cohesive failure) and the absolute peelvalues are similar for UV-cured and dark-cured samples.

The hardness of a polythioether/polyene-based sealant using aMn(III)(acetylacetonate)₃/tert-butylperoxybenzoate catalyst as the darkcure catalyst is shown in FIG. 3. The applied sealant was exposed to UVradiation at 395 nm for 3 sec (224 mW/cm²). The test sample consisted ofa panel to which a 0.25-inch (6.35 mm) thick layer of sealant wasapplied. FIG. 3 shows the Shore A hardness of sealants exposed to UV,room fluorescent lighting (RL), and without exposure to UV (dark cureconditions).

The depth of cure for a polythioether/polyalkenyl-based sealant usingMn(III)(acetylacetonate)₃/tert-butylperoxybenzoate catalyst is shown inFIG. 4. FIG. 4 shows the hardness of the sealant with depth. The sealantwas exposed to UV radiation at 395 nm for 30 sec (224 mW/cm²) and theShore A hardness was measured at depths from 6 mm to 14 mm. The sealantcured to a depth of 8 mm immediately following exposure to the UVradiation. The sealant cured (hardness greater than Shore 40A) to adepth of 12 mm to 14 mm within 24 hours. At 4 days, the UV-exposed anddark-cure samples had an identical hardness of Shore 48A.

The physical properties (tensile strength and tensile elongation) of apolythioether/polyene-based sealant using aMn(III)(acetylacetonate)₃/tert-butylperoxybenzoate catalyst is shown inFIG. 5. After three (3) days, the tensile strength and the tensileelongation of the UV-cured and the dark-cured sealant was comparable.

The Part A and Part B compositions were stable as determined by therebeing no change in the viscosity of the compositions when maintained at120° F. (49° C.) for 14 days (limit of testing) or at 140° F. (60° C.)for 7 days (limit of testing) in dark conditions. In other studies, theconcentration of organic peroxide in Part A and theMn(III)(acetylacetonate)₃ concentrations were increased to 3 times and1.5 times, respectively. Again, after 14 days at 120° F. (49° C.) therewas nt change in the viscosity indicating that the compositions werestorage stable.

FIG. 6 shows the effect of the composition of the dark cure catalystMn(III)(acetylacetonate)₃/tert-butylperoxybenzoate on the curing rate asreflected in the sample hardness with time. Dark cure catalyst systemshaving different amounts of organic peroxide (tert-butylperoxybenzoate)and metal catalyst (Mn(III)(acetylacetonate)₃) were prepared as in Table8:

TABLE 8 Dark cure catalyst compositions. Sample Sample Sample SampleCatalyst 6(1) 6(2) 6(3) 6(4) tert-Butylperoxybenzoate wt %¹ 1 1 0.5 0.5Mn(III)(acetylacetonate)₃, wt %¹ 0.5 0.25 0.5 0.25 Total Catalyst, wt %¹1.5 1.25 1 1 Organic peroxide/Metal Complex 2 4 1 2 Weight Percent Ratio¹Based on the total weight of the composition

The hardness of sealants containing the various dark cure catalystconcentrations were measured at three (3) days and at seven (7) daysfollowing application. The hardness of samples exposed to roomfluorescent lighting was also measured. The results are shown in FIG. 6.The depth of cure was also determined and the results are shown in FIG.7.

The results shown in FIGS. 6 and 7 demonstrate that a concentration oforganic peroxide as low as 0.75 wt % and a metal complex as low as 0.5wt % can be used to provide a full dark cure within three (3) days. Theapplication time of these compositions was 30 min, i.e., B-1/2 (30-minextrusion, workable for 30 min). The physical properties includinghardness, tensile/elongation, and peel strength of the dark-curedsealants are comparable to those of the UV-cured sealants.

A Fe(III)(acetylacetonate)₃/tert-butylperoxybenzoate dark cure catalystwas also evaluated. The application time as reflected in the extrusionrate (B-1/2; greater than 30 min) with time after mixing the polythiol(Part B) and polyalkenyl (Part A) components is shown in FIG. 8. Theresults show that the practical application time for this system isgreater than 2 hours (extrusion rate is greater than 100 g/min).

FIG. 9 shows the effect of the composition of the dark cure catalystFe(III)(acetylacetonate)₃/tert-butylperoxybenzoate on the curing rate asreflected in the sample hardness with time. Dark cure catalyst systemshaving different amounts of organic peroxide (tert-butylperoxybenzoate)and metal catalyst (Fe(III)(acetylacetonate)₃) were prepared as in Table9:

TABLE 9 Dark cure catalyst compositions. Sample Sample Sample Sample9(1) 9(2) 9(3) 9(4) tert-Butylperoxybenzoate wt % 1 1.89 1.89 1.89Fe(III)(acetylacetonate)₃, wt % 0.29 0.15 0.07 0.039 Total Catalyst, wt% 1.29 2.04 1.96 1.929 Organic Peroxide/Metal Complex 3.4 12.6 27.0 48.5Weight Percent Ratio

The hardness and depth of cure of sealants containing the various darkcure catalyst concentrations were measured (a) eight (8) days after UVexposure, (b) 3 days exposed to room fluorescent lighting (RL), (c)eight (8) days under dark conditions, or (d) twelve (12) days under darkconditions. The results are shown in FIG. 9.

The metal complexes are provided as solutions containing a solvent andanion. For example, Fe(III)(acetylacetonate)₃ can be provided as a 10%solution of toluene and acetylacetonate. To evaluate the effects of themetal complex solvent composition on the properties of a dark curedsealant, Fe(III)(acetylacetonate)₃ solutions having different solventcompositions were prepared having the solvent compositions shown inTable 10:

TABLE 10 Metal complex solvent composition. 10(1) 10(2) 10(3) 10(4)10(5) 10(6) Acetylacetonate, 25 50 75 10 5 1 wt %¹ Toluene, wt %¹ 75 5025 90 95 99 ¹Based on the total weight of the combined solvents.

For these solutions wt % represents the wt % of the total solvent.

Sealants were prepared having 1.89 wt % organic peroxide(tert-butylperoxybenzoate) and 0.10 wt % of theFe(III)(acetylacetonate)₃ solutions shown in Table 10. The hardness andthe cure depth of the cured sealants was measured 12 days followingapplication and further exposed to (a) UV, (b) UV after twelve (12)days, (c) room fluorescent lighting (RL) after 12 days, or darkconditions after twelve (12) days. Also, sealants with aFe(III)(acetylacetonate)₃ solution having 100% toluene gelled within 15min.

The curing rate as reflected by the hardness of a sealant containingFe(III)(acac)₃ and tert-butyl peroxybenzoate is shown in FIG. 11. Thedepth of cure for this sealant was 6 mm immediately following exposureto UV (394 nm for 30 sec at 224 mW/cm²) and the depth of cure was 10 mmafter one (1) day. The physical properties (tensile/elongation) for thesealant is shown in FIG. 12. The peel strength as determined accordingto AS 5127/1C, is summarized in Table 11:

TABLE 11 Peel strength of cured sealants. Dark Cure UV Cured Peel DarkCure Peel UV Cured Strength Failure Strength Failure Substrate lb/inMode lb/in Mode AMS 2471 29 100% 32 100% (6111-44 primer¹) cohesivecohesive AMS 27725 28 100% 30 100% (6111-44 primer) cohesive cohesiveAMS 5513/16 — — 23 100% cohesive (6111-44 primer) (thin film)¹Prehydrolyzed organosilane primer available from PPG Aerospace.

Based on these results, for theFe(III)(acetylacetonate)₃/tert-butylperoxybenzoate catalyst, theconcentration of the metal complex can be as low as 0.07 wt % and theconcentration of the organic peroxide can be as low as 1.5 wt %, wherewt % is based on the total weight of the curable composition. Under darkcure conditions the sealant fully cures within 8 days. The applicationtime is greater than 2 h, i.e., 30 min or longer. The physicalproperties including hardness, tensile/elongation, and peel strength ofthe dark-cured sealants are comparable to those of the UV-cured sealant.The results suggest the concentration of metal complex can be reduced towithin a range from 0.02 wt % to 0.05 wt %; however, at theseconcentrations the time to fully cure under dark conditions can belonger. Also, the results suggest that adjusting the solvent/anion ratioof the metal complex solution can be used to adjust the dark cure time.

The fuel resistance of compositions provided by the present disclosurewas also evaluated. The results are presented in Table 12:

TABLE 12 Fuel resistance of cured sealants. 12(1) 12(2) 12(3) 12(4) DarkCure UV Cure 1 day/RL Dark Cure Metal complex Fe(III)(acac)₃Fe(III)(acac)₃ Fe(III)(acac)₃ Mn(III)(acac)₃ 0.1 wt %¹ 0.1 wt % 0.1 wt %1.0 wt % 10% solution 10% solutions 10% solution 10% solutions Dry Peel20 (8 day)  25 25 30 (3 day) Strength, lb/in 30 (11 day) Dry Peel 20%Cohesive 100% Cohesive 100% cohesive 100% cohesive Failure Mode  (8 day)Some surface 20% Cohesive tack (11 day) JRF Type I >20 30 30 20 lb/inJRF Type I 20% cohesive 100% Cohesive 100% Cohesive 100% CohesiveFailure Mode ¹Based on wt % of the curable composition; catalyst in 10wt % solution of acetyl acetone.

The sealants were applied to an AMS 27725, 6111-44 primed substrate.Peel strength was determined according to AS 5127/1C.

In summary, based on the results for the UV-curable composition(unmodified composition−control) the UV-cured sealant exhibits atensile/elongation of 450 psi/250%, a hardness of Shore 48A, and a peelstrength on several substrates greater than 25 lb/in (0.45 kg/mm). Thesame dark-cured sealant exhibits comparable physical and adhesiveproperties at 3 days for the Mn(III)-based sealant and at 8 days for theFe(III)-based sealant.

It was also observed that standard room fluorescent lighting acceleratescuring to a greater extent than dark cure alone. Sealants containing theFe(III)-based catalyst cure faster under fluorescent lighting than docomparable Mn(III)-based systems and unmodified UV-curable compositions.

Example 5 Short Cure, Dual Cure Formulations

Short-cure sealant formulations having the components as shown in Table13. Trigonox® C, tert-butyl peroxybenzoate) in the specified wt % wasadded to the combined Part A and Part B where wt % is based on the totalweight of Part A, Part B, and Trigonox® C. The metal catalyst andadditive was added to in the specified wt % where wt % is based on thetotal weight of Part A, Part B, and Trigonox® C. The samples wereprepared in a total amount of about 50 g.

TABLE 13 Short-cure sealant formulations. Organic Sample Part A Part BPeroxide Metal Complex Additive  1 Example 1, Example 1, Trigonox ®Mn(acac)₃, 0.5 wt % ¹ Ce(NH₄)(NO₃)₆, 0.26 Part A Part B C, 1.0 wt % wt %² Ratio B:A 100:8.2  2 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25wt % ¹ Part A Part B C, 1.0 wt % 2,2′-bipyridyl, 0.25 Ratio B:A wt % ³100:8.2  3 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹Silquest ® A-1100, Part A Part B C, 1.0 wt % 0.25 wt % Ratio B:A (aminesource) 100:8.2  4 Example 1, Example 1, Trigonox ® Mn(acac)₃ 0.5 wt % ¹Myribond ™, 0.5 wt % ⁵ Part A Part B C, 1.0 wt % Ratio B:A 100:8.2  5Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.5 wt % ¹ ethyl 4- Part APart B C, 1.0 wt % (dimethylamino) Ratio B:A benzoate ; 0.5 wt % ⁶100:8.2 (amine synergist)  6 Example 1, Example 1, Trigonox ® Mn(acac)₂,1.0 wt % ⁷ Part A Part B C, 1.0 wt % Ratio B:A 100:8.2  7 Example 1,Example 1, Trigonox ® Mn(acac)₂, 1.0 wt %⁷ Part A Part B C, 1.25 wt %Ratio B:A 100:8.2  8 Example 1, Example 1, Trigonox ® Mn(acac)₃ 0.5 wt %¹ Part A Part B C, 1.25 wt % Ratio B:A 100:8.2  9 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.5 wt % ¹ Part A Part B C, 1.0 wt % Mn(acac)₂,0.3 wt % ⁷ Ratio B:A 100:8.2 10 Example 1, Example 1, Trigonox ®Mn(acac)₃, 0.5 wt % ¹ Ascorbic acid, 1 wt % ⁸ Part A Part B C, 1.0 wt %Ratio B:A 100:8.2 11 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.5 wt% ¹ p-tolyldiethanol Part A Part B C, 1.0 wt % amine, 0.5 wt % ⁹ RatioB:A 100:8.2 12 Example 1, Example 1, Trigonox ® Mn(acac)₃p-tolyldiethanol Part A Part B C, 1.0 wt % amine 0.5 wt % ¹⁰ Ratio B:A100:8.2 13 Example 1, Example 1, Trigonox ® Mn(acac)3:2,2′- Part A PartB C, 1.0 wt % bipyridyl ¹¹ Ratio B:A 100:8.2 13A Example 1, Example 1,Trigonox ® Mn(acac)₃:2,2′- Part A Part B C, 1.0 wt % bipyridyl ¹¹ RatioB:A 100:8.2 14 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹Part A Part B C, 1.0 wt % V(acac)₃, 0.25 wt % ¹² Ratio B:A 100:8.2 15Example 1, Example 1, Trigonox ® V(acac)₃: Part A Part B C, 1.0 wt %2,2-bipyridyl, 0.5 Ratio B:A wt % ¹³ 100:8.2 16 Example 1, Example 1,Trigonox ® V(acac)3:2,2- Part A Part B C, 1.0 wt % bipyridyl , 0.25 wt %¹³ Ratio B:A 100:8.2 17 Example 1, Example 1, Trigonox ® Mn(acac)₃:2,2-Part A Part B C, 1.0 wt % bipyridyl, 0.5 wt % ¹⁴ Ratio B:A 100:8.2 18Example 1, Example 1, Trigonox ® Mn(acac)₃:2,2- Part A Part B C, 1.0 wt% bipyridyl, 1.0 wt % ¹⁴ Ratio B:A 100:8.2 19 Example 1, Example 1,Trigonox ® Mn(acac)₃ p-tolyldiethanol Part A Part B C, 1.0 wt % amine0.75 wt % ¹⁰ Ratio B:A 100:8.2 20 Example 1, Example 1, Trigonox ®V(acac)₃:2,2- Part A Part B C, 1.0 wt % bipyridyl, 0.25 wt % ¹³ RatioB:A 100:8.2 21 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹⁵Part A Part B C, 1.0 wt % Ratio B:A 100:8.2 22 Example 1, Example 1,Trigonox ® V(acac)₃:2,2- Part A Part B C, 1.0 wt % bipyridyl, 0.375 wt %¹³ Ratio B:A 100:8.2 23 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25wt % ¹ p-tolyldiethanol Part A Part B C, 1.0 wt % amine, 0.5 wt % ⁹Ratio B:A 100:8.2 24 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt% ¹ p-tolyldiethanol Part A Part B C, 1.0 wt % amine, 0.25 wt % ⁹ RatioB:A 100:8.2 25 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.125 wt % ¹p-tolyldiethanol Part A Part B C, 1.0 wt % amine, 0.25 wt % ⁹ Ratio B:A100:8.2 26 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.125 wt % ¹p-tolyldiethanol Part A Part B C, 1.0 wt % amine, 0.375 wt % ⁹ Ratio B:A100:8.2 27 Example 1, Example 1, none Mn(acac)₃, 0.125 wt % ¹ Vazo ®-67,1.0 wt % ¹⁶ Part A Part B Ratio B:A 100:8.2 28 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.125 wt % ¹ p-tolyldiethanol Part A Part B C, 1.0wt % amine, 0.5 wt % ⁹ Ratio B:A 100:8.2 28R Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.125 wt % ¹ p-tolyldiethanol Part A Part B C, 1.0wt % amine, 0.5 wt % ⁹ Ratio B:A 100:8.2 29 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.25 wt % ¹ S-1535 (stearic acid Part A Part B C,1.0 wt % intermediate), 1 Ratio B:A wt % ³³ 100:8.2 30 Example 1,Example 1, none V(acac)₃:2,2- Vazo ®-67, 1.0 wt % ¹⁶ Part A Part Bbipyridyl ,0.15 wt % ¹³ Ratio B:A 100:8.2 31 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.25 wt % ¹ triethanolamine, Part A Part B C, 1.0wt % 0.375 wt % ¹⁷ Ratio B:A 100:8.2 32 Example 1, Example 1, Trigonox ®Mn(acac)₃, 0.25 wt % ¹ triethanolamine, 0.5 Part A Part B C, 1.0 wt % wt% ¹⁷ Ratio B:A 100:8.2 33 Example 1, Example 1, Trigonox ® Mn(acac)₃,0.25 wt % ¹ S-1535 (stearic acid Part A Part B C, 1.0 wt %intermediate), 1 Ratio B:A wt % ³³ 100:8.2 33R Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.25 wt % ¹ S-1535 (stearic acid Part A Part B C,1.0 wt % intermediate), 1 wt % Ratio B:A 100:8.2 34 Example 1, Example1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ 4-N,N- Part A Part B C, 1.0 wt %trimethylaniline, 0.5 Ratio B:A wt % ¹⁸ 100:8.2 35 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.25 wt % ¹ 5-vinyl-2-norbomene, Part A Part B C,1.0 wt % 0.5 wt % ¹⁹ Ratio B:A 100:8.2 36 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.25 wt % ¹ 4-N,N- Part A Part B C, 1.0 wt %trimethylaniline, 0.5 Ratio B:A wt % ¹⁸ 100:8.2 37 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Ethacure ® 100, 0.5 Part A Part B C,1.0 wt % wt % ²⁰ Ratio B:A 100:8.2 38 Example 1, Example 1, Trigonox ®Mn(acac)₃, 0.5 wt % ¹ Part A Part B C, 1.0 wt % Ratio B:A 100:8.2 39Example 1, Example 1, Trigonox ® Mn acetate dihydrate Part A Part B C,1.0 wt % 0.5 wt % ¹ Ratio B:A 100:8.2 40 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Ethacure ® 100, 0.25 Part A Part B C,1.0 wt % wt % ²⁰ Ratio B:A 100:8.2 41 Example 1, Example 1, Trigonox ®Mn(acac)₃, 0.25 wt % ¹ Ethacure ® 100, 0.125 Part A Part B C, 1.0 wt %wt % ²⁰ Ratio B:A 100:8.2 42 Example 1, Example 1, Trigonox ® Mn(acac)₃,0.125 wt % ¹ Ethacure ® 100, Part A Part B C, 1.0 wt % 0.125 wt % ²⁰Ratio B:A 100:8.2 43 Example 1, Example 1, Trigonox ® No metal catalystEthacure ® 100, Part A Part B C, 1.0 wt % 0.5 wt % ²⁰ Ratio B:A 100:8.244 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Ethacure ®300, Part A Part B C, 1.0 wt % 0.25 wt % ²⁰ Ratio B:A 100:8.2 45 Example1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Ethacure ® 300, Part APart B C, 1.0 wt % 0.125 wt % ²⁰ Ratio B:A 100:8.2 46 Example 1, Example1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Ethacure ® 300, Part A Part B C,1.0 wt % 0.06125 wt % ²⁰ Ratio B:A 100:8.2 47 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Part A Part B C, 1.0 wt % Ratio B:A100:8.2 48 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹2,5-diphenylfuran ²¹ Part A Part B C, 1.0 wt % Ratio B:A 100:8.2 49Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ 9,16- Part APart B C, 1.0 wt % dimethylanthracene ²² Ratio B:A 100:8.2 50 Example 1,Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Part A Part B C, 1.0 wt %Ratio B:A 100:8.2 51 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt% ¹ Part A Part B C, 1.0 wt % Ratio B:A 100:8.0 52 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Part A Part B C, 1.0 wt % Ratio B:A100:7.8 53 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ PartA Part B C, 1.0 wt % Ratio B:A 100:8.4 54 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Part A Part B C, 1.0 wt % Ratio B:A100:8.6 55 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ PartA Part B C, 1.0 wt % CHDMDVE replaced with TEGDVE (2.7% higher HBVE)Ratio B:A 100:7.6 56 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt% ¹ p-tolyldiethanol Part A Part B C, 1.0 wt % amine, 0.25 wt % ⁹CHDMDVE replaced with TEGDVE (2.7% higher HBVE) Ratio B:A 100:7.6 37Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ p-toluidine,0.25 wt % ²³ Part A Part B C, 1.0 wt % Replaced CHDMDVE with TEGDVE(2.7% higher HBVE) Ratio B:A 100:7.6 58 Example 1, Example 1, Trigonox ®Mn(acac)₃, 0.25 wt % ¹ p-toluidine, 0.375 Part A Part B C, 1.0 wt % wt %²³ CHDMDVE replaced with TEGDVE (2.7% higher HBVE) Ratio B:A 100:7.6 59Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ p-toluidine,0.375 Part A Part B C, 1.0 wt % wt % ²³ CHDMDVE replaced with TEGDVE(2.7% higher HBVE) Ratio B:A 100:7.6 60 Example 1, Example 1, Trigonox ®Mn(acac)₃, 0.25 wt % ¹ Part A Part B C, 1.0 wt % CHDMDVE replaced withTEGDVE (2.7% higher HBVE) Ratio B:A 100:7.2 61 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.5 wt % ¹ Part A Part B C, 1.0 wt % CHDMDVEreplaced with TEGDVE (2.7% higher HBVE) Ratio B:A 100:7.2 62 Example 1,Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ p-toluidine, 0.25 wt % ²³Part A Part B C, 1.0 wt % CHDMDVE replaced with TEGDVE (2.7% higherHBVE) Ratio B:A 100:7.2 63 Example 1, Example 1, Trigonox ® Mn(acac)₃,0.25 wt % ¹ p-toluidine, 0.125 Part A Part B C, 1.0 wt % wt % ²³ CHDMDVEreplaced with TEGDVE (2.7% higher HBVE) Ratio B:A 100:7.2 64 Example 1,Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ p-tolyldiethanol Part APart B C, 1.0 wt % amine, 0.25 wt % ⁹ CHDMDVE replacedwith TEGDVE (2.7%higher HBVE) Ratio B:A 100:7.2 65 Example 1, Example 1, Trigonox ®Mn(acac)₃, 0.25 wt % ¹ p-tolyldiethanol Part A Part B C, 1.0 wt % amine,0.125 wt % ⁹ CHDMDVE replaced with TEGDVE (2.7% higher HBVE) Ratio B:A100:7.2 66 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹Tetramethylthiuram Part A Part B C, 1.0 wt % disulfide, 0.25 wt % ²⁴CHDMDVE replaced with TEGDVE (2.7% higher HBVE) Ratio B:A 100:7.2 67Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ tris(2- Part APart B C, 1.0 wt % pyridylmethyl)amine, CHDMDVE 0.25 wt % ²⁵ replacedwith TEGDVE (2.7% higher HBVE) Ratio B:A 100:7.2 68 Example 1, Example1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Part A Part B C, 1.0 wt % Iron(II)sulfate CHDMDVE heptahydrate, 0.10 replaced with wt % ²⁶ TEGDVE onweight basis Ratio B:A 100:7.5 69 Example 1, Example 1, Trigonox ®Mn(acac)₃, 0.25 wt % ¹ Part A Part B C, 1.0 wt % Iron(II) sulfateCHDMDVE heptahydrate, 0.35 replaced with wt % ²⁶ TEGDVE on weight basisRatio B:A 100:7.5 70 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt% ¹ Part A Part B C, 1.0 wt % Iron(III)(acac)₃, 0.07 CHDMDVE wt % ²⁷replaced with TEGDVE on weight basis Ratio B:A 100:7.5 71 Example 1,Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Part A Part B C, 1.0 wt %Iron(III)(acac)₃, 0.10 CHDMDVE wt % ²⁷ replaced with TEGDVE on weightbasis Ratio B:A 100:7.5 72 Example 1, Example 1, Trigonox ® Mn(acac)₃,0.25 wt % ¹ Part A Part B C, 1.0 wt % Iron(III)(acac)₃, 0.07 CHDMDVE wt% ²⁷ replaced with TEGDVE on weight basis Ratio B:A 100:7.5 73 Example1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Part A Part B C, 1.0 wt% Iron(II) sulfate CHDMDVE heptahydrate ,0.5 replaced with wt %^(26, 28) TEGDVE on weight basis Ratio B:A 100:7.5 74 Example 1, Example1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Part A Part B C, 1.0 wt % Iron(II)sulfate CHDMDVE heptahydrate, 0.35 replaced with wt % ^(26, 29) TEGDVEon weight basis Ratio B:A 100:7.5 75 Example 1, Example 1, Trigonox ®Mn(acac)₃, 0.25 wt % ¹ Methyl propyl Part A Part B C, 1.0 wt % ketone, 1wt % CHDMDVE (solvent) replaced with TEGDVE on weight basis Ratio B:A100:7.5 76 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹ Ethylacetate, 1 wt % Part A Part B C, 1.0 wt % (solvent) CHDMDVE replacedwith TEGDVE on weight basis Ratio B:A 100:7.5 79 Example 1, Example 1,Trigonox ® Mn(acac)₃, 0.25 wt % ¹ isopropanol, 1 wt % Part A Part B C,1.0 wt % (solvent) 80 CHDMDVE Mn(acac)₃, 0.25 wt % ¹ hexanes, 1 wt %replaced with (solvent) 81 TEGDVE on Mn(acac)₃, 0.25 wt % ¹ methanol, 1wt % weight basis (solvent) 82 Ratio B:A Mn(acac)₃, 0.25 wt % ¹cyclohexane, 1 wt % 100:7.5 (solvent) 83 Mn(acac)₃, 0.25 wt % ¹ toluene,1 wt % (solvent) 84 Mn(acac)₃, 0.25 wt % ¹ Distilled water, 1 wt %(solvent) 85 Example 1, Example 1, Trigonox ® Mn(acac)₃, 0.25 wt % ¹Firstcure MHPT, Part A Part B C, 1.0 wt % 0.25 wt % ³¹ 86 CHDMDVEMn(acac)₃, 0.25 wt % ¹ Firstcure MHPT, replaced with 0.375 wt % ³¹ 87TEGDVE on Mn(III)-stearate, 0.25 weight basis wt % ³² 88 Ratio B:AMn(III)-stearate, 0.5 100:7.5 wt % ³² ¹ 10% solution acetylacetone. ²10% solution in water. ³ 10% solution in acetylacetone. ⁴ Used as asource of amine to modulate surface cure. ⁵ Myriant, Myr174-6; tack timemodifier. ⁶ 10% solution in acetylacetone; used as an amine synergist tomodulate surface cure ⁷ 5% solution in acetylacetone; Mn(II)(acac)₂ hasmuch lower solubility in (acac) and was solubilized by heating to 140°F. “for 4 h. ⁸ 10% solution in acetylacetone; oxygen scavenger. ⁹ 10%solution in acetylacetone. ¹⁰ 0.5 wt % of a 10% solution of 1:1 moleratio of Mn(acac)₃ and p-tolyldiethanol amine in acetylacetone. ¹¹ 0.5wt % of a 10% solution of 1:1 mole ratio of Mn(acac)₃ and 2,2′-bipyridylin acetylacetone. ¹² 10% solution in acetylacetone. ¹³ 10% solution of1:2 moles of V(acac)₃:2,2′-bipyridyl in HB-40. ¹⁴ 10% solution of 1:2moles of Mn(acac)₃:2,2′-bipyridyl in HB-40. ¹⁵ 10% solution of Mn(acac)₃in toluene. ¹⁶ 50% solution in acetylacetone. ¹⁷ 10% solution inacetylacetone. ¹⁸ Neat. ¹⁹ mixture of endo and exo 95%, contains 80-150ppm BHT as inhibitor (Aldrich); neat; contains 80-150 ppm BHT (butylatedhydroxytoluene) as inhibitor (Aldrich); tack time modifier. ²⁰ 10%solution in acetylacetone. ²¹ 1 mole equivalent of Mn(acac)₃, of2,5-diphenylfuran:7.8 mg in 0.25 g of acetylacetone; free radicalscavenger. ²² 1 mole equivalent of Mn(acac)₃, of9,16-dimethylanthracene:7.3 mg in 0.25 g of acetylacetone; UVsensitizer. ²³ 10% solution in acetylacetone. ²⁴ 10% solution in HP-40in acetylacetone; UV sensitizer. ²⁵ 10% solution in acetylacetone. ²⁶10% solution in distilled water. ²⁷ 10% solution in acetylacetone. ²⁸Both catalysts were added at the same time to Parts A and B. ²⁹ Ironcatalyst was added first to Parts A and B, mixed, and then the Mncatalyst was added. ³⁰ 10% solution in distilled water. ³¹ 10% solutionin acetylacetone, Albemarle; amine accelerator. ³² Mn(III)-stearatecomplex was prepared by combining 3 eq stearic acid dissolved in ethylacetate) for 3 h at 25° C. Stearic acid was dissolved in thienyl acetateas 10% solution. ³³ Tack time modifier.

Note that the metal complexes were added to the sealant composition as adilute solution. For example, Mn(acac)₃ was provided as 10 wt %Mn(acac)₃ in a solution of acetylacetone. Adding 1 wt % of this 10%Mn(acac)₃ solution to a composition effectively adds 0.1 wt % of theMn(acac)₃ complex to the composition.

Example 6 Adhesion of Short Cure. Dual Cure Formulations

The adhesion of UV- and dark-cured samples was determined for theShort-Cure Formulation 1 (see Table 13), which included Mn(acac)₃ as themetal complex and Ce(NH₄)(NO₃)₆ as a nitrogen synergist. The adhesionwas tested on AMS 27725, AMS 4911, 2024-T3, AMS 2471, and AMS 5516substrates. Test panels were treated with a RW 6111-44 surface primer(available from PPG Aerospace). A 0.125-inch (3.175-mm) thick layer ofthe formulation was applied to the primed substrate. The samples wereeither exposed to 1 J/cm² to 2 J/cm² of UVA radiation or cured in thedark at 25° C. for several hours. The peel strength and cohesive failurewas determined according to AS 5127/1C. The results are shown in Table14.

TABLE 14 Adhesion of Short-Cure Formulation 1 cured under UV- and darkcure conditions. Peel Panel Exposure Peel (lbs/in) Cohesive AMS 27725 UV45 sec 19 100% Dark 40 hr 39 100% AMS 4911 UV 45 sec 19 100% Dark 30 hr28 100% 2024-T3 UV 45 sec 16  50% Dark 40 hr 23  50% AMS 2471 UV 45 sec33  90% Dark 40 hr 33 100% AMS 5516 UV 45 sec 24 100% Dark 40 hr 37 100%

The adhesion of UV- and dark-cured samples was determined for theShort-Cure Formulation 1 (see Table 13), which included Mn(acac)₃ as themetal complex and Ce(NH₄)(NO₃)₆ as a nitrogen synergist followingimmersion in Jet Reference Fluid (JRF) Type I or NaCl solution. Theadhesion was tested on AMS 27725, AMS 4911, 2024-T3, AMS 2471, and AMS5516 substrates. Test panels were treated with a RW 6111-44 surfaceprimer (available from PPG Aerospace). A 0.125-inch (3.175-mm) thicklayer of the formulation was applied to the primed substrate. Thesamples were either exposed to 1 J/cm² to 2 J/cm² of UVA radiation, orcured in the dark for about 40 hours. The samples were immersed in JRFType I for 7 days at 60° C. followed by 3 days at 25° C., according toAMS 2620, Rev. E, or to a 3% NaCl solution for 7 days at 60° C. followedby 3 days at 25° C. The results are shown in Table 15 and in Table 16,respectively.

TABLE 15 Adhesion of Short-Cure Formulation 1 cured under UV- and darkcure conditions and following immersion in Jet Reference Fluid Type I.Peel Panel Exposure Peel (lbs/in) Cohesive Delamination AMS 27725 UV 2070% 30% Dark 35 25% 75% AMS 4911 UV 25 10% 90% Dark 40 20% 80% 2024-T3UV 30 80% 20% Dark 30 50% 50% AMS 2471 UV 35 20% 80% Dark 25  5% 90% AMS5516 UV 20 60%  0% Dark 35 80% 20%

TABLE 16 Adhesion of Short-Cure Formulation 1 cured under UV- and darkcure conditions and following immersion in 3% NaCl solution. Peel PanelExposure Peel (lbs/in) Cohesive Delamination AMS 27725 UV 23 95%  5%Dark 30 20% 80% AMS 4911 UV 25 70% 30% Dark 40 20% 80% 2024-T3 UV 27 90%10% Dark 28 40% 60% AMS 2471 UV 25 10% 90% Dark 30 10% 90% AMS 5516 UV18 40%  0% Dark 28 20% 80%

Example 7 Heat Resistance of Short Cure, Dual Cure Formulations

The heat resistance properties of UV- and dark-cured samples wasdetermined for the Short-Cure Formulations 3 and 10 (see Table 13)according to AMS 3277J Section 3.6.21 (Heat Cycle Test). Theseformulations had an application time from 30 min to 45 min. Test panelswere treated with a RW 6111-44 surface primer (prehydrolyzedorganosilane primer available from PPG Aerospace). A 0.125-inch(3.175-mm) thick layer of either Formula 3 or Formulation 10 was appliedto the primed substrate. The samples were either exposed to 1 J/cm² to 2J/cm² of UVA radiation or cured in the dark for about 72 hours.Following cure, the samples were immersed in JRF Type I for 7 days at60° C. (AMS 2629) followed by 3 days air dry at 49° C. and 7 days heataging at 149° C. (300° F.). The results for Formulation 3 andFormulation 10 are shown in Table 17 and in Table 18, respectively.

TABLE 17 Heat Resistance of Short Cure Formulation 3. Following Exposureto Initial AMS 3277J Heat Cycle Tensile Tensile Hardness StrengthElongation Hardness strength Elongation Shore Cure (psi) (%) Shore A(psi) (%) A UV 374 ± 13 276 ± 17 47 241 ± 27 160 ± 19 47 Dark 347 ± 7 335 ± 12 45 253 ± 29 154 ± 16 45

TABLE 18 Heat Resistance of Short Cure Formulation 10. FollowingExposure to Initial AMS 3277J Heat Cycle Tensile Tensile HardnessStrength Elongation Hardness strength Elongation Shore Cure (psi) (%)Shore A (psi) (%) A UV 320 ± 16 272 ± 10 47 251 ± 26 187 ± 28 46 Dark391 ± 3  325 ± 13 45 215 ± 30 210 ± 29 45

Example 8 Application and Tack Free Time of Short Cure, Dual CureFormulations

The application time (AT) and the tack free time (TFT) for variousshort-cure formulations containing cure profile modifiers wasdetermined. Test samples were prepared by combining the components forseveral short cure formulations as shown in Table 13. Application timewas determined as the duration from the time the components werecombined to the time the sealant exhibited an extrusion rate of 15 g/minwhen extruded through a No. 440 nozzle (Semco, 0.125-inch internaldiameter and 4-inch length, available from PPG Aerospace) at a pressureof 90 psi (620 KPa). The open time was determined by applying a0.125-inch thick coating of the sealant to a substrate, and at intervalswhile the sealant cured, applying a polyethylene sheet to the sealantsurface with hand pressure, removing the polyethylene sheet andobserving whether any sealant adhered to the polyethylene sheet. Thetack free time was the duration from the time the sealant componentswere first combined to the time when no sealant was observed on thepolyethylene sheet.

The results shown in FIG. 13, demonstrate that a wide range ofapplication times and tack free times can be obtained by selecting themetal catalyst(s) and additive(s). The formulation number is referred inthe table.

FIG. 14 shows the Shore A hardness of fully cured sealants under UV anddark cure conditions. Sealant components were combined according toTable 13, and the sealant formulations applied to a substrate to athickness of 0.125 inches (3.175 mm). For the UV cured samples, thesealants were exposed to 1 J/cm² to 2 J/cm² of UVA radiation, andmaintained at 25° C. for 7 days. The initial Shore A hardness of thesealants within a few minutes following exposure to UV and the resultsare shown in FIG. 15. For the dark cured samples, the sealants werestored under dark conditions at 25° C. for 7 days. The Shore A hardnesswas measured according to ASTM D2240 using a Type A durometer.

The application time, tack free time, and initial Shore A hardness ofseveral short cure sealant formulations included in Table 13 are shownin Table 19. The application time was determined by extrusion asdescribed herein. The tack free time by applying a polyethylene sheet tothe sealant surface with hand pressure and observing adhesion of thesealant. The initial Shore A hardness was measured within a few minutesfollowing exposure to The UVA radiation. In general, for manyapplications it can be desirable that the application time be at least30 minutes, the tack free time be at least 25 hours, and the initialhardness following exposure to UV be at least Shore 35A. Formulations11, 12, 26, and 28-R included an amine synergist. Sealant formulations14 and 20 included a co-catalyst. Sealant formulation 73 included anoxygen scavenger.

TABLE 19 Application time, tack free time an initial hardness of shortcure sealant formulations. Sealant Application Tack Free Shore AFormulation Time (min) Time(hr) Hardness (Initial)  6 30 48 35 10 30 4830 11 30 16 30 12 30 20 43 14 60 16 35 15 20 5 42 16 60 36 40 17 300 4838 18 120 48 38 19 30 48 32 20 30 18 40 21 35 48 40 22 25 5 40 23 20 1542 24 30 15 40 25 55 25 35 26 40 20 35 28R 40 20 36 29 45 48 42 31 80 4834 32 75 48 31 34 50 24 36 36 20 24 37 37 10 17 35 40 15 18 44 41 15 1844 46 20 26 42 47 30 36 36 49 30 36 35 50 40 24 45 55 60 48 41 56 30 4840 62 40 36 42 65 30 30 45 68 50 48 46 69 40 48 45 73 30 20 27 74 40 2444

FIGS. 16A and 16B show the application time and open time, respectively,for certain of the sealant formulations in Table 13, in a chart format.

Example 9 Physical Properties of Long Cure. Dual Cure Formulations

The physical properties of various long cure sealants shown in Table 20was determined following UV and dark cure. The results are presented inTable 21 for the dark cured sealants, and in Table 22 for the UV curedsealants. The hardness was measured for the fully cured samples used forthe tensile/elongation measurements. In general, for certainapplications, it can be desirable that the tensile strength be greaterthan 200 psi (1.38 MPa) and the % elongation be greater than 300%.

TABLE 20 Long-cure sealant formulations. Organic Metal Complex SamplePart A Part B Peroxide or Compound Additive LC-1 Example 1, Example TBPBBorchi ® OXY- NA Part A 1, Part B 2 wt %¹ coat 1310⁶ 1.1 Ratio B:A wt %100:8.2 LC-2 Example 1, Example TBPB 15% Potassium NA Part A 1, Part B 2wt % Hex-cem ®⁷ 0.2 Ratio B:A wt % 100:8.2 LC-3 Example 1, Example TBPB10% NA Part A 1, Part B 0.5 wt % Fe(III)(acac)₃ in Ratio B:A acac 0.16wt % 100:8.2 LC-4 Example 1, Example TBPB 10% NA Part A 1, Part B 0.5 wt% Fe(III)(acac)₃ in Ratio B:A acac 0.08 wt % 100:8.2 LC-5 Example 1,Example TBPB Polycure ® 503⁸ NA Part A 1, Part B 2 wt % 0.12 wt % RatioB:A 100:8.2 LC-6 Example 1, Example NA NA NA Part A 1, Part B Ratio B:A100:8.2 LC-7 Example 1, Example TBPB 7.7% Al(acac)₃ NA Part A 1, Part B1 wt % in 60/40 Ratio B:A toluene/acac 100:8.2 0.75 wt % LC-8 Example 1,Example TBPB 15% Potassium NA Part A 1, Part B 1 wt % Hex-cem ® 0.2Ratio B:A wt % 100:8.2 LC-9 Example 1, Example TBPB 7.7% Al(acac)₃ NAPart A 1, Part B 0.5 wt % in 60/40 Ratio B:A toluene/acac 100:8.2 0.75wt % LC-10 Example 1, Example TBPB 10% NA Part A 1, Part B 0.5 wt %Fe(III)(acac)₃ in Ratio B:A acac 0.04 wt % 100:8.2 LC-11 Example 1,Example TBPB 10% NA Part A 1, Part B 0.25 wt % Fe(III)(acac)₃ in RatioB:A acac 0.04% 100:8.2 LC-12 Example 1, Example TBPB 10% NA Part A 1,Part B 1 wt % Mn(III)(acac)₃ Ratio B:A in acac 0.25%; 100:8.2 S-5135 1wt % LC-13 Example 1, Example TBPB 10% Ethacure ® NA Part A 1, Part B 1wt % 100 in acac 0.5 Ratio B:A wt % 100:8.2 LC-14 Example 1, Example BPO10% NA Part A 1, Part B 1 wt %² Mn(III)(acac)₃ Ratio B:A in acac 0.25100:8.2 wt % LC-15 Example 1, Example Butanox ® 10% NA Part A 1, Part BP-50 Mn(III)(acac)₃ Ratio B:A 1 wt %³ in acac 0.25 100:8.2 wt % LC-16Example 1, Example APS 10% NA Part A 1, Part B 1 wt %⁴ Mn(III)(acac)3Ratio B:A in acac 0.25 100:8.2 wt % LC-17 Example 1, Example TBPB 10%Ethacure ® NA Part A 1, Part B 1 wt % 100 in acac 0.75 Ratio B:A wt %100:8.2 LC-18 Example 1, Example TBPB NA 10% MHPT⁹ in Part A 1, Part B 1wt % acac 0.5% Ratio B:A 100:8.2 LC-19 Example 1, Example TBPB NA 10%TDEA¹⁰ in Part A 1, Part B 1 wt % acac 0.5% Ratio B:A 100:8.2 LC-20Example 1, Example TBPB NA 10% toluidine in Part A 1, Part B 1 wt % acac0.5% Ratio B:A 100:8.2 LC-21 Example 1, Example TBPB Borchi ® OXY- NAPart A 1, Part B 2 wt % coat 1310 1.1 Ratio B:A wt % 100:8.2 LC-22Example 1, Example APS NA 10% MHPT in Part A 1, Part B 0.1 wt % acac0.1% Ratio B:A 100:8.2 LC-23 Example 1, Example TBPB 10% NA Part A 1,Part B 0.25 wt % Fe(III)(acac)₃ in Ratio B:A acac 0.02 wt % 100:8.2LC-24 Example 1, Example TBPB 10% NA Part A 1, Part B 0.125 wt %Fe(III)(acac)₃ in Ratio B:A acac 0.01 wt % 100:8.2 LC-25 Example 1,Example APS NA 10% MHPT in Part A 1, Part B 0.1 wt % acac 0.5% Ratio B:A100:8.2 LC-26 Example 1, Example APS NA 10% MHPT in Part A 1, Part B 0.2wt % acac 0.5% Ratio B:A 100:8.2 LC-27 Example 1, Example APS 10% NAPart A 1, Part B 0.2 wt % Mn(III)(acac)₃ Ratio B:A in acac 0.25 100:8.2wt % LC-28 Example 1, Example Butanox ® NA 10% MHPT in Part A 1, Part BP-50 acac 0.5% Ratio B:A 1 wt % 100:8.2 LC-29 Example 1, Example BPO NA10% toluidine in Part A 1, Part B 0.2% acac 0.5% Ratio B:A 100:8.2 LC-30Example 1, Example BPO NA 10% MHPT in Part A 1, Part B 0.2 wt % acac 0.5wt % Ratio B:A 100:8.2 LC-31 Example 1, Example TBPB NA 10% MHPT in PartA 1, Part B 1 wt % acac 0.75 wt % Ratio B:A 100:8.2 LC-32 Example 1,Example TBPB NA 10% TDEA in Part A 1, Part B 1 wt % acac 0.75 wt % RatioB:A 100:8.2 LC-33 Example 1, Example BPO 10% NA Part A 1, Part B 0.7 wt% Fe(III)(acac)₃ in Ratio B:A acac 0.16 wt % 100:8.2 LC-34 Example 1,Example TBPB 10% 10%MHPT in Part A 1, Part B 1 wt % Fe(III)(acac)₃ inacac 0.5 wt % Ratio B:A acac 0.02% 100:8.2 LC-35 Example 1, Example TBPB10% 10% TDEA in Part A 1, Part B 1 wt % Fe(III)(acac)₃ in acac 0.5 wt %Ratio B:A acac 0.02 wt % 100:8.2 LC-36A Example 1, Example TBPB 10% NAPart A 1, Part B 1 wt % Mn(III)(acac)₃ Ratio B:A in acac 0.5 wt %100:8.2 LC-36B Example 1, Example TBPB 1 wt % 10% NA Part A 1, Part B inGasil ® Mn(III)(acac)₃ Ratio B:A IJ35⁵ in acac 0.5 wt % 100:8.2 LC-37Example 1, Example TBPB 10% 10% TDEA in Part A 1, Part B 0.54 wt %Fe(III)(acac)₃ in acac 0.5 wt % Ratio B:A acac 0.02 wt % 100:8.2 LC-38Example 1, Example TBPB Borchi ® OXY- 10% TDEA in Part A 1, Part B 0.54wt % coat 1310 acac 0.5 wt % Ratio B:A 0.02 wt % 100:8.2 LC-39 Example1, Example TBPB Borchi ® OXY- 10% TDEA in Part A 1, Part B 0.54 wt %coat 1310 acac 0.5 wt % Ratio B:A 0.2 wt % 100:8.2 LC-40 Example 1,Example TBPB 10% 10% MHPT in Part A 1, Part B 0.54 wt % Fe(III)(acac)₃in acac 0.5 wt % Ratio B:A acac 0.02 wt % 100:8.2 LC-41 Example 1,Example TBPB Borchi ® OXY- 10% MHPT in Part A 1, Part B 0.54 wt % coat1310 0.02 acac 0.5 wt % Ratio B:A wt % 100:8.2 LC-42 Example 1, ExampleTBPB Borchi ® OXY- 10% MHPT in Part A 1, Part B 0.54 wt % coat 1310 0.2acac 0.5 wt % Ratio B:A wt % 100:8.2 LC-43 Example 1, Example TBPB 15%Potassium 10% TDEA in Part A 1, Part B 0.54 wt % Hex-cem ® acac 0.5 wt %Ratio B:A 0.2 wt % 100:8.2 LC-44 Example 1, Example TBPB 10% FeSO₄ in NAPart A 1, Part B 0.54 wt % H₂O 0.05 wt % Ratio B:A 100:8.2 LC-45 Example1, Example TBPB 10% 10% MHPT in Part A 1, Part B 1 wt % Fe(III)(acac)₃in acac 1 wt % Ratio B:A acac 0.02 wt % 100:8.2 LC-46 Example 1, ExampleTBPB 10% 10% TDEA in Part A 1, Part B 1 wt % Fe(III)(acac)₃ in acac 1 wt% Ratio B:A acac 0.02 wt % 100:8.2 LC-47 Example 1, Example TBPBBorchi ® OXY- 10% TDEA in Part A 1, Part B 1 wt % coat 1310 acac 1 wt %Ratio B:A 0.4 wt % 100:8.2 LC-48 Example 1, Example TBPB 15% Potassium10%TDEA in Part A 1, Part B 1 wt % Hex-cem ® acac 1 wt % Ratio B:A 0.4wt % 100:8.2 LC-49 Example 1, Example TBPB Borchi Oxy-coat 10%TDEA inPart A 1, Part B 1% 1310 0.2 wt % acac 1 wt % Ratio B:A 100:8.2 LC-50Example 1, Example TBPB 15% Potassium 10% TDEA in Part A 1, Part B 0.5%Hex-cem ® acac 1 wt % Ratio B:A 0.2 wt % 100:8.2 LC-51 Example 1,Example TBPB 15% Potassium 10% TDEA in Part A 1, Part B 1% Hex-cem ®acac 0.5% Ratio B:A 0.2 wt % 100:8.2 LC-52 Example 1, Example TBPB 15%Potassium 10% TDEA in Part A 1, Part B 0.5 wt % Hex-cem ® acac 0.5 wt %Ratio B:A 0.4 wt % 100:8.2 ¹tert-Butyl peroxide benzoate, Trigonox ® C,wt % is acetylacetone (AkzoNobel). ²Benzoyl peroxide. ³Butonox ® P-50,methyl isopropyl ketone peroxide, solution in dimethyl phthalate(AkzoNobel). ⁴Ammonium persulfate. ⁵Gasil ® IJ35, silica gel, averageparticle size 4.6-5.8 μm, 1.2 mL/g pore volume (PQ Corporation).⁶Borchi ® OXY-Coat 1310, 1% solution of an iron complex in dipropyleneglycol monomethyl ether and 1,2-propylene glycol (Borchers). ⁷Potassiumhex-cem ®, potassium 2-ethylhexanoate dissolved in diethylene diglycol(Borchers). ⁸Poly-cure ® 503, blend of metal salts of 2-ethylhexanoicacid (Borchers). ⁹MHPT, FirstCure ® MHPT,N-(2-hydroxyethyl)-N-methyl-para-toluidine (Albemarle). ¹⁰TDEA,N,N-diethyltoluene-2,5-diamine.

TABLE 21 Physical properties of long cure sealants cured under darkconditions. Sealant Cure Time Tensile Strength Elongation HardnessFormulation (days) (psi) (%) (Shore A) LC-45 22 277 374 36 LC-35 27 319391 40 LC-10 42 340 362 40 LC-11 42 348 380 40 LC-46 22 218 385 36 LC-4822 330 401 39

TABLE 22 Physical properties of long cure sealants cured under UVconditions. Sealant Days After Tensile Strength Elongation HardnessFormulation UV Cure (psi, SD) (%, SD) (Shore A) LC-45 2 449 (22) 292(18) 48 LC-35 28 412 (25) 334 (20) 47 LC-10 2 435 (36) 360 (37) 47 LC-112 439 (24) 388 (30) 47 LC-46 2 451 (22) 300 (16) 47 LC-48 2 436 (10) 273(13) 47

The Shore A hardness of certain fully cured short cure sealants shown inTable 13 cured under UV or dark conditions are shown in FIG. 17.

The initial Shore A hardness of certain short cure sealants shown inTable 13 measured within a few minutes following exposure to UV is shownin FIG. 18.

The effects of certain solvents on the application time, tack free time,and initial (UV cure) hardness of various sealants presented in Table13, is shown in Table 23.

TABLE 23 Application time, open time, and hardness of various short curesealants under UV and dark cure conditions. Initial Dark Room UVFollowing Conditions Lighting Conditions Open Tack UV Hardness HardnessHardness Time Free Hardness) (Shore A) (Shore A) (Shore A) SealantSolvent (min) (hr) (Shore A) at 24 hr at 24 hr at 24 hr 75 methyl 9036-48 43 39-48 38-48 46-48 propyl ketone 76 ethyl acetate 90 48 43 39-4838-48 48 79 isopropanol 120 24 43 34 34 47 80 hexanes 90 24 43 35 32 4781 methanol 120-150 36 43 38 36 47 82 cyclohexane 90 36 44 34 33 47 83toluene 90 36 42 33 32 46 84 water 80 36 43 32 28 47

Finally, it should be noted that there are alternative ways ofimplementing the embodiments disclosed herein. Accordingly, the presentembodiments are to be considered as illustrative and not restrictive.Furthermore, the claims are not to be limited to the details givenherein, and are entitled to their full scope and equivalents thereof.

What is claimed is:
 1. A composition comprising: a polythiol, whereinthe polythiol comprises a thiol-terminated prepolymer; a polyalkenyl,wherein the polyalkenyl comprises an alkenyl-terminated prepolymer, apolyalkenyl monomer, or a combination thereof; a metal complex; and anorganic peroxide.
 2. The composition of claim 1, wherein thethiol-terminated prepolymer comprises a thiol-terminatedsulfur-containing prepolymer.
 3. The composition of claim 2, wherein thethiol-terminated sulfur-containing prepolymer comprises athiol-terminated polythioether prepolymer, a thiol-terminatedpolysulfide prepolymer, a thiol-terminated sulfur-containing polyformalprepolymer, a thiol-terminated monosulfide prepolymer, or a combinationof any of the foregoing.
 4. The composition of claim 3, wherein thethiol-terminated sulfur-containing prepolymer comprises athiol-terminated polythioether prepolymer.
 5. The composition of claim4, wherein the thiol-terminated sulfur-containing prepolymer comprises amoiety having the structure of Formula (2c):—S—R¹—[S-A-S—R¹—]_(n)—S—  (2c) wherein, n is an integer from 1 to 60;each R¹ is independently selected from C₂₋₁₀ alkanediyl, C₆₋₈cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, C₅₋₈heterocycloalkanediyl, and —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—, wherein, pis an integer from 2 to 6; q is an integer from 1 to 5; r is an integerfrom 2 to 10; each R³ is independently selected from hydrogen andmethyl; and each X is independently selected from O, S, and NR, whereinR is selected from hydrogen and methyl; and each A is independently amoiety derived from a polyvinyl ether of Formula (3) and a polyalkenylpolyfunctionalizing agent of Formula (4):CH₂═CH—O—(R²—O)_(m)—CH═CH₂  (3)B(—R⁷⁰—CH═CH₂)_(z)  (4) wherein, m is an integer from 0 to 50; each R²is independently selected from C₁₋₁₀ alkanediyl, C₆₋₈ cycloalkanediyl,C₆₋₁₄ alkanecycloalkanediyl, and —[(CHR³)_(p)—X—]_(q)(CHR³)_(r)—,wherein p, q, r, R³, and X are as defined as for R¹; B represents a coreof a z-valent, polyalkenyl polyfunctionalizing agent B(—R⁷⁰—CH═CH₂)_(z)wherein, z is an integer from 3 to 6; and each R⁷⁰ is independentlyselected from C₁₋₁₀ alkanediyl, C₁₋₁₀ heteroalkanediyl, substitutedC₁₋₁₀ alkanediyl, and substituted C₁₋₁₀ heteroalkanediyl.
 6. Thecomposition of claim 1, wherein the polythiol comprises a polythiolmonomer.
 7. The composition of claim 1, wherein the polyalkenyl monomercomprises a bis(alkenyl) ether.
 8. The composition of claim 1, whereinthe metal complex comprises cobalt(II)bis(2-ethyl hexanoate),manganese(III)(acetylacetonate)₃, iron(III)(acetylacetonate)₃, or acombination of any of the foregoing.
 9. The composition of claim 1,wherein the organic peroxide comprises tert-butyl peroxybenzoate. 10.The composition of claim 1, wherein the metal complex comprises a metalcomplex of Co(II), Co(III), Mn(II), Mn(III), Fe(II), Fe(III), Cu(II),V(III), or a combination of any of the foregoing.
 11. The composition ofclaim 1, wherein the curable composition comprises a free radicalphotoinitiator.
 12. The composition of claim 1, wherein the curablecomposition comprises a hydrogen donor.
 13. The composition of claim 1,wherein the hydrogen donor comprises a primary amine, a secondary amineor a combination thereof.
 14. The composition of claim 1, wherein thecomposition comprises from 0.01 wt % to 2 wt % of a primary amine, asecondary amine, a tertiary amine, or a combination thereof, wherein wt% is based on the total weight of the composition.
 15. The compositionof claim 1, wherein the composition comprises: from 45 wt % to 85 wt %of the thiol-terminated sulfur-containing prepolymer; from 1 wt % to 10wt % of the polyalkenyl; from 0.001 wt % to 2 wt % of the metal complex;and from 0.1 wt % to 5 wt % of the organic peroxide, wherein wt % isbased on the total weight of the composition.
 16. The composition ofclaim 1, wherein the composition is curable under dark conditions. 17.The composition of claim 1, wherein, the composition is curable uponexposure to actinic radiation; and the composition is curable withoutexposure to actinic radiation.
 18. The composition of claim 1, whereinthe composition is curable at a temperature from 20° C. to 30° C.
 19. Acured sealant prepared from the composition of claim
 1. 20. A partsealed with the cured sealant of claim
 19. 21. A vehicle comprising thecured sealant of claim
 19. 22. An aerospace vehicle comprising the curedsealant of claim
 19. 23. A method of sealing a part comprising: applyingthe composition of claim 1 to a part; and allowing the appliedcomposition to cure, to seal the part.